Implement exit relay lifecycle
We recently merged a community proposal about introducing an exit relay lifecycle (see: tpo/community/policies#32 (closed) for details). Now we need to get this implemented in c-tor.
While, thanks to the merged proposal, we already have a specification for this new feature, it doesn't replace the required torspec one specifying the implementation details. So, we need a technical spec first.
There have been discussions and PoC code for this feature in different tickets/merge requests. The important pieces can be found in tpo/community/policies#32 (comment 3274953) and tpo/network-health/team#220.