document rdsys, bridgestrap, and bridgedb in TPA service pages

Hi!

It would be great if you could make documentation for the services ran by the anti-censorship team inside TPA infrastructure and/or at least make sure (existing) docs are linked from the service page here:

https://gitlab.torproject.org/tpo/tpa/team/-/wikis/service

We currently have only "gettor" documented in there, and the documentation is quite minimal, the equivalent of the "Pager playbook" section of the template:

https://gitlab.torproject.org/tpo/tpa/team/-/wikis/howto/template

In tpo/anti-censorship/gettor-project/gettor#77 (comment 2728419), @cohosh identified "rdsys, bridgestrap, and bridgedb" as services running on polyanthum that should be documented, but there might be more!

I am aware that the documentation template is quite extensive. ;) You don't necessarily have to fill it all up, the most critical stuff to fill in is the "Pager playbook" and "Disaster recovery" sections. But I think it's a good template to start from when documenting a service. We're still working on the documentation, and your feedback on how it works will be extremely valuable! :)