Github multi-repo view

[hans-d]

What should it do?

In addition to #1312:

for custom queries spanning multiple repos, it would be good to show the repo it's coming from.
(Also the links need to point to the correct repo, they now use the repo that's being "viewed/selected"

In general:
I'm not interested in prs from a single repo, I want to track them for a collection of repos.

[stale]

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