* Repo collab now supports basic default roles developer/user/guest like
project collab does
* User/Anon collab for repos and projects are now stored as fields instead of
in dedicated tables, there was never a need for dedicated tables but I didn't
see that before
* Repo push op is now part of `ProjectOperation`
* `RepoRole` and related code has been entirely removed, only project roles
remain and they're used for both repos and projects
* This is the first not-totally-trivial DB migration in Vervis, it's automatic
but please be careful and report errors
The sharer and repo were being taken and used as is to check push permissions,
which is how it's supposed to be, *but* they were also being used as is to
build the repo path! So sharer and repo names that aren't all lowercase were
getting "No such repository" errors when trying to push.
I changed `RepoSpec` to hold `ShrIdent` and `RpIdent` instead of plain `Text`,
to avoid confusions like that and be clear and explicit about the
representation, and failures to find a repo after verifying it against the DB
are now logged as errors to help with debugging.
I hope this fixes the problem.
This is a lot of code, better save now than sorry later when something
gets deleted by mistake.
Either way, the code will move later - once tested and organized
properly - into its own package.
