feat(cli): add command line interface with comprehensive features

Implements a full-featured CLI for Crawl4AI with the following capabilities:
- Basic and advanced web crawling
- Configuration management via YAML/JSON files
- Multiple extraction strategies (CSS, XPath, LLM)
- Content filtering and optimization
- Interactive Q&A capabilities
- Various output formats
- Comprehensive documentation and examples

Also includes:
- Home directory setup for configuration and cache
- Environment variable support for API tokens
- Test suite for CLI functionality

docs/examples/cli/browser.yml

@@ -0,0 +1,13 @@
+browser_type: "chromium"
+headless: true
+viewport_width: 1280
+viewport_height: 800
+user_agent_mode: "random"
+verbose: true
+text_mode: false
+light_mode: false
+ignore_https_errors: true
+java_script_enabled: true
+extra_args:
+  - "--disable-gpu"
+  - "--no-sandbox"