## Problem
As part of the reldirv2 rollout: LKB-197.
We will use number of db/rels as a criteria whether to rollout reldirv2
directly on the write path (simplest and easiest way of rollout). If the
number of rel/db is small then it shouldn't take too long time on the
write path.
## Summary of changes
* Compute db/rel count during basebackup.
* Also compute it during logical size computation.
* Collect maximum number of db/rel across all timelines in the feature
flag propeties.
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
## Problem
Follow up of #12400
## Summary of changes
We didn't set remote_size_mb to Some when initialized so it never gets
computed :(
Also added a new API to force refresh the properties.
Signed-off-by: Alex Chi Z <chi@neon.tech>
## Problem
Part of #11813
## Summary of changes
Add a test API to make it easier to manipulate the feature flags within
tests.
---------
Signed-off-by: Alex Chi Z <chi@neon.tech>
