Move hardcoded rowlimit out of the storage implementation

[rbev]

Moves the existing 200-group limit from persistence implementation into the API, changed it to explicitly request a single 200 group page instead of relying the the storage tier to limit it.

• Adds PagingInfo to unresolved and archived group-list datastore methods.
• Requests page 1 with a page size of 200 from both APIs
• Applies paging within RavenDB and EF Core queries.
• Removes persistence-owned .Take(200) calls and FailureGroupQueries.MaxGroups.
• Adds shared contract tests for unresolved and archived group paging.
• Preserves existing response metadata and GroupFetcher merge behavior.

[johnsimons]

It is unclear to me what is the benefit of moving the cheese this way.
I actually think that the next person touching this will look at it and say, ah the api already supports paging, so let me add paging to the frontend! Without really taking into consideration lots of other factors.

I think a better option, is to document what we spoke about in the slack thread in the code itself.

[warwickschroeder]

@johnsimons - i think im missing context here. Could you elaborate on what the other factors are?