* Add CustomBridge
For advanced users. Create RSS feed using HTML selectors.
* [CssSelectorBridge] Refactor, Allow Unexpanded
Rename bridge to CssSelectorBridge
Allow unexpanded feed, i.e. make feed from home page only (1 request)
Refactor bridge to put most of the code into protected functions
Makes the code more maintainable and allows inheritance for variants
* [CssSelectorBridge] Fix linting
