feat/flask: Small fixes and maintenance

- Fixed encoding error when reading locale.ini
- Added redirect from "/" route to "/en" route
- Added ifmain to app.py to fix Flask console error
- Added .gitignore for Flask
- Added requirements.txt

[feat/flask] Small infrastructure fixes

- Added Dockerfile and .env in .gitignore (just in case)
- Sorted .gitignore
- Removed Flask dependencies from requirements.txt

.gitignore

@@ -0,0 +1,21 @@
+# Editors
+.idea/
+.vscode/
+
+# Python
+.venv*/
+venv*/
+__pycache__/
+dist/
+
+# Unit tests
+.coverage*
+htmlcov/
+.tox/
+
+# Docs
+docs/_build/
+
+# Our's
+Dockerfile
+.env