Optimize Docker (#575)

* reduce docker dev size

* reduce docker prod size

* fix lint

* add gunicorn

* fix bandit reported issues

* add docs external link icon

* add env vars to docs

* add permission to docker

* merge to one backend Dockerfile

* fix codefactor issues

* add docs for puid/pgid

* add docker healthcheck

.dockerignore

@@ -1,3 +1,27 @@
+.git
+.github
+.dockerignore
+.gitignore
+
+.idea
+.vscode
+
+__pycache__/
+*.py[cod]
+*$py.class
+*.so
+htmlcov/
+.coverage
+.coverage.*
+.pytest_cache/
+.venv
+venv
+
+.DS_Store
+.AppleDouble
+.LSOverride
+._*
+
 */node_modules
 */dist
 */data/db