feat(browser-farm): Add Docker browser support for remote crawling

Implement initial MVP for Docker-based browser management in Crawl4ai, enabling
remote browser execution in containerized environments.

Key Changes:
- Add browser_farm module with Docker support components:
  * BrowserFarmService: Manages browser endpoints
  * DockerBrowser: Handles Docker browser communication
  * Basic health check implementation
  * Dockerfile with optimized Chrome/Playwright setup:
    - Based on python:3.10-slim for minimal size
    - Includes all required system dependencies
    - Auto-installs crawl4ai and sets up Playwright
    - Configures Chrome with remote debugging
    - Uses socat for port forwarding (9223)

- Update core components:
  * Rename use_managed_browser to use_remote_browser for clarity
  * Modify BrowserManager to support Docker mode
  * Add Docker configuration in BrowserConfig
  * Update context handling for remote browsers

- Add example:
  * hello_world_docker.py demonstrating Docker browser usage

Technical Details:
- Docker container exposes port 9223 (mapped to host:9333)
- Uses CDP (Chrome DevTools Protocol) for remote connection
- Maintains compatibility with existing managed browser features
- Simplified endpoint management for MVP phase
- Optimized Docker setup:
  * Minimal dependencies installation
  * Proper Chrome flags for containerized environment
  * Headless mode with GPU disabled
  * Security considerations (no-sandbox mode)

Testing:
- Extensive Docker configuration testing and optimization
- Verified with hello_world_docker.py example
- Confirmed remote browser connection and crawling functionality
- Tested basic health checks

This is the first step towards a scalable browser farm solution, setting up
the foundation for future enhancements like resource monitoring, multiple
browser instances, and container lifecycle management.

docs/md_v2/advanced/managed_browser.md

@@ -63,7 +63,7 @@ async with AsyncWebCrawler(config=config) as crawler:
 ```
 
 ### Managed Browser
-The `ManagedBrowser` class offers a high-level abstraction for managing browser instances, emphasizing resource management, debugging capabilities, and anti-bot measures.
+The `RemoteConnector` class offers a high-level abstraction for managing browser instances, emphasizing resource management, debugging capabilities, and anti-bot measures.
 
 #### How It Works
 - **Browser Process Management**:
@@ -82,7 +82,7 @@ The `ManagedBrowser` class offers a high-level abstraction for managing browser
 - **Scalability**:
   - Handles multiple browser instances concurrently, scaling dynamically based on workload.
 
-#### Example: Using `ManagedBrowser`
+#### Example: Using `RemoteConnector`
 ```python
 from crawl4ai import AsyncWebCrawler, BrowserConfig