The new version of Flow is requiring declarations to provide explicit type params when Flow isn't able to infer them. This diff adds those declarations in most cases that aren't specific enough to be covered in another diff.
This is the keyserver equivalent of D9695 (lib) and D9775 (web).
NOTE: CI will fail on this diff. I considered the possibility of fixing Flow errors BEFORE upgrading Flow, but it wasn't possible... in some cases, the fixes to support the new version of Flow caused errors in the old version. I could have hidden these type errors with $FlowFixMe lines and then later revert those, but that seemed like too much busy work.
Depends on D9863