[REF] use single main branch with per-version config directories

Replace per-branch versioning (16.0, 18.0...) with a single main branch
containing version-specific subdirectories under config/.

Structure:
- config/common/: shared files deployed to all versions
- config/16.0/: Odoo 16.0 specific configs (pylintrc, ruff, pre-commit)

The deploy workflow now:
- Triggers on push to main
- Auto-detects available versions from config/*/
- For each target repo, deploys common + version-specific files

Also enables Gitea native cache in pre-commit workflow.

config/common/.editorconfig

@@ -0,0 +1,20 @@
+# Configuration for known file extensions
+[*.{css,js,json,less,md,py,rst,sass,scss,xml,yaml,yml}]
+charset = utf-8
+end_of_line = lf
+indent_size = 4
+indent_style = space
+insert_final_newline = true
+trim_trailing_whitespace = true
+
+[*.{json,yml,yaml,rst,md}]
+indent_size = 2
+
+# Do not configure editor for libs and autogenerated content
+[{*/static/{lib,src/lib}/**,*/static/description/index.html,*/readme/../README.rst}]
+charset = unset
+end_of_line = unset
+indent_size = unset
+indent_style = unset
+insert_final_newline = false
+trim_trailing_whitespace = false