Gettor feature complete

* Add a gitlab gettor updater
* Add prometheus metrics to gettor distributor
* Fix multiple gettor issues
* Distribute only bridgestrap tested and functional resources
* Ignore bridge authority updates without running bridges
* Include the location of the request to the Circumvention Settings API
* Add support to bridgelines in Circumvention map
* Circumvention Settings distributes dummy bridges if not valid
  shim-token provided
* Add an API to update Telegram dynamic bridges
* UX improvements in Telegram distributor

Telegram improvements for deployment

* Use both dynamic and bridge authority bridges for old telegram
  accounts
* Add tests to telegram distributor

Circumvention Settings API and Telegram distributors

* Add Circumvention settings API
* Add Telegram distributor
* Fix the use of the distibution request for bridges

First rdsys version

* Full support for bridges in the backend
* Using BridgeDB as distributor