Refactor site testing and management tools

- Removed `site_tester.py` and integrated its functionality into `site_manager.py` as `SimpleSiteTester`.
- Added comprehensive site management features in `site_manager.py`, including image optimization, site building, serving, and statistics generation.
- Introduced a new command-line interface for managing the MkDocs site with various commands (build, serve, optimize, stats, test, check, clean).
- Implemented image optimization to convert JPG/JPEG/PNG images to WebP format and update markdown references accordingly.
- Added media path checking functionality to ensure all media references are valid.
- Created a structured report for site statistics and testing results.
- Updated `.dockerignore` to exclude unnecessary files and directories.

Author: f@bi.an

.dockerignore

@@ -0,0 +1,7 @@
+letsencrypt/
+certbot/
+.git/
+.gitignore
+*.md
+.github/
+.dockerignore

.gitignore

@@ -6,4 +6,12 @@ site/
 .qodo
 .venv/
 __pycache__/
-.cache/
+.cache/
+letsencrypt/
+certbot/
+*.log
+*.env
+*.pem
+*.crt
+*.key
+*.p12