Refactor docker deployment and user setup (#863)

* Fix #862, address #826 and maybe some other tickets: reimplemented the docker-compose user setup to enhance product setup experience and cover much more cases.

* make unique DB container name and use it in communication from Photoview

* Removed unnecessary healthcheck for photoview from docker-compose.example.yml, as it is defined in the Dockerfile; optimized Dockerfile combining all RUN directives of PROD stage into 1, which will produce single layer and save some space; added Dockerfile-dev, docker-compose-dev.yml, and new "dev" and "dev-down" directives into Makefile, which allows to setup development env in Docker. Instructions of how to use it are in comments at the beginning of Dockerfile-dev and docker-compose-dev.yml files

* Set RWX permissions to the application's working folder for any user, so that the image could be later run with non-root permissions and the app still be able to do needed operations in the FS

* Enhanced the "Getting started" section in the readme; added the `help` target and enhanced comments in the Makefile; commented out the `docker system prune -f` with the comment about the command and why it is there; added optional and commented by default `7zz` commands to the `backup` section of the Makefile

* Use `slim` base image for final photoview image

* Implement SQLite support according to the PR #851

* Removed deprecated `version` line from compose files; optimized dockerfile to build with less layers and run as non-root; mapped only Photoview related services to Watchtower by default instead of updating all running images on a host; added template for Postgres to the .env; reverted compose executable definition, so the new compose is called when present; added a tip about `lnav` to help

* fix a typo in the username; add support of PostgreSQL; split and optimize backup target in Makefile

* Fixed some typos and styling in Readme, excluded dev-environment setup from the PR; added a list of tips on how to secure Photoview in the Advanced setup section of Readme

* Implemented many security improvements, suggested by @Omar007, switched to the dedicated Darktable's repo to install the latest released version, as asked in #935; switched Watchtower to labels instead of profiles

* forgot the compose file

* move face models back to /app folder; comment out and document unnecessary vars in compose; fix a typo in a few vars

* Exclude Makefile in the root folder from git; documented multiple mounts case better; fixed incorrect SQLite DB path

* Fixed several bugs after complete testing cycle with all 3 DBs

* removed hardcoded port in Dockerfile

* Pin the major version for the `photoview` image for stability

* Revert back to the port 80 inside the container on product owner's request

* Provide a minimal compose file and update the readme accordingly

* Handle incorrect media file and folder permissions; set correct permissions for storage folder; fix healthcheck command for postgres

---------

Co-authored-by: Konstantin Koval <kkb@ukr.net>

docker-compose example/example.env

@@ -0,0 +1,62 @@
+##================***================##
+## These are the environment setup variables.
+## Start setting up your instance from here.
+## Syntax of the .env file is next:
+## VARIABLE_NAME=variable value with everything after the '=' and till the end of the line.
+## The variables with values, set in the docker-compose.yml directly, are for advanced configuration.
+##================***================##
+
+##----------Host variables-----------##
+## This is the current folder, where all Photoview files and folders (except of your media library) are located
+HOST_PHOTOVIEW_LOCATION=/opt/photoview
+
+## This is where your original photos and videos located.
+## Provide here the path to single root folder for your media collection.
+HOST_PHOTOVIEW_MEDIA_ROOT=/your/root/media/folder
+## If you'd like to map multiple folders from different locations, create additional variables
+## here like the next one and modify the docker-compose.yml to match them and use in volume mappings.
+# HOST_PHOTOVIEW_MEDIA_FAMILY=/full/path/to/folder
+
+## This is where the Photoview data will be backed up
+HOST_PHOTOVIEW_BACKUP=/media/Backup/PhotoView
+##-----------------------------------##
+
+##-------Photoview variables---------##
+## PHOTOVIEW_DATABASE_DRIVER could have one of values: `mysql` (default), `sqlite`, `postgres`
+PHOTOVIEW_DATABASE_DRIVER=mysql
+
+## Optional: To enable map related features, you need to create a mapbox token.
+## A token can be generated for free here https://account.mapbox.com/access-tokens/
+## It's a good idea to limit the scope of the token to your own domain, to prevent others from using it.
+# MAPBOX_TOKEN=yourToken
+##-----------------------------------##
+
+##--------MariaDB variables----------##
+## Comment out these variables if PHOTOVIEW_DATABASE_DRIVER is `sqlite` or `postgres`
+## Use password generator to generate secret values and replace these defaults
+MARIADB_DATABASE=photoview
+MARIADB_USER=photoview
+MARIADB_PASSWORD=photosecret
+MARIADB_ROOT_PASSWORD=superphotosecret
+##-----------------------------------##
+
+##---------SQLite variables----------##
+## Uncomment the next line if PHOTOVIEW_DATABASE_DRIVER is `sqlite`
+# PHOTOVIEW_SQLITE_PATH=/home/photoview/database/photoview.db
+##-----------------------------------##
+
+##-------PostgreSQL variables--------##
+## Uncomment the next lines if PHOTOVIEW_DATABASE_DRIVER is `postgres`
+# PGSQL_DATABASE=photoview
+# PGSQL_USER=photoview
+# PGSQL_PASSWORD=superphotosecret
+## See https://www.postgresql.org/docs/current/libpq-ssl.html for possible ssl modes
+# PGSQL_SSL_MODE=prefer
+##-----------------------------------##
+
+##-------Watchtower variables--------##
+## The POLL_INTERVAL in sec
+WATCHTOWER_POLL_INTERVAL=86400
+WATCHTOWER_TIMEOUT=30s
+WATCHTOWER_CLEANUP=true
+##\\\\\\\\\\\\\\\\\//////////////////##