refactor: build only one frappe/erpnext image (#1032)

* ci: skip frappe builds

* refactor: build only one frappe/erpnext image

* fix: lint nginx entrypoint script

* docs: update and organize docs

* docs: fix lint errors

* fix(custom): pass base64 encoded apps json

* ci: update dependabot

* docs: update contributing

* docs: remove info about multi image setup

* fix: initiate empty common_site_config.json

default config has host keys set to localhost
causes connection errors

* docs: add details for pwd volumes

* fix: symlink assets instead of copy

* fix: nginx private files

* ci: skip docker compose v2 install for ubuntu-latest

* fix: organize layers

* feat: allow remove git remote for custom image

* docs: allow remove git remote for custom image

* fix: remove duplicate --apps_path

docs/site-operations.md

@@ -9,7 +9,7 @@ Note:
 - Wait for the `db` service to start and `configurator` to exit before trying to create a new site. Usually this takes up to 10 seconds.
 
 ```sh
-docker-compose exec backend bench new-site <site-name> --mariadb-root-password <db-password> --admin-password <admin-password>
+docker-compose exec backend bench new-site <site-name> --no-mariadb-socket --mariadb-root-password <db-password> --admin-password <admin-password>
 ```
 
 If you need to install some app, specify `--install-app`. To see all options, just run `bench new-site --help`.
@@ -24,7 +24,7 @@ docker-compose exec backend bench set-config -g root_password <root-password>
 Also command is slightly different:
 
 ```sh
-docker-compose exec backend bench new-site <site-name> --db-type postgres --admin-password <admin-password>
+docker-compose exec backend bench new-site <site-name> --no-mariadb-socket --db-type postgres --admin-password <admin-password>
 ```
 
 ## Push backup to S3 storage