Initial commit: Maskarr - Tracker proxy for *arr apps

- HTTP proxy server to modify User-Agent and headers for private trackers
  - Web UI with collapsible tracker cards and real-time validation
  - Multi-tracker support with persistent JSON configuration
  - Thread-safe configuration management
  - Full HTTP methods support (GET, POST, PUT, DELETE, PATCH, HEAD, OPTIONS)
  - REST API for tracker management
  - Docker support with multi-architecture builds (amd64, arm64, arm/v7)
  - CI/CD workflows for GitHub Actions and Gitea Actions
  - Automatic publishing to GitHub Container Registry and Gitea Registry

.dockerignore

@@ -0,0 +1,35 @@
+# Git
+.git
+.gitignore
+.github
+.gitea
+
+# Python
+__pycache__
+*.py[cod]
+*$py.class
+*.so
+.Python
+*.egg-info/
+dist/
+build/
+.venv/
+venv/
+
+# Config files (will be mounted as volume)
+maskarr_config.json
+
+# Documentation
+*.md
+LICENSE
+
+# IDE
+.vscode/
+.idea/
+*.swp
+*.swo
+*~
+
+# OS
+.DS_Store
+Thumbs.db