* refactor: bridgefactory, add tests * refactor: move defaultly enabled bridges to config * refactor * refactor * feat: add support for enabling bridges with env var
* refactor * fix: case-sensitive config from env, fix #2935 * lowercase all config section and keys * test: add test for case-insensitivity
This fixes a future problem when code is placed under a namespace because `get_class($bridge)` will then return e.g. `RssBridge\Bridge\TwitterBridge` instead of the the current value `TwitterBridge`. Also a bit refactoring of `Configuration.php`.
