RFR: 1851: Fold CSR bot into PR bot [v3]

[Zhao Song]

On Tue, 28 Mar 2023 15:51:50 GMT, Erik Joelsson <erikj at openjdk.org> wrote:

>> At first, I had the same idea with you and later I found it a little complex to implement it. But if we let all CSRIssueBots share a map, it would be very easy. If you think it's necessary to change, I will fix it.
>
> I suppose it doesn't matter if they share the map, but the test does not need to verify that they do, or that a `CSRIssueBot` for a certain `IssueProject` is able to look up a `PullRequestBot` for a different IssueProject. The test should only verify that the relevant PullRequestBots are available.

Yes, at least I will change the test here.

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PR Review Comment: https://git.openjdk.org/skara/pull/1492#discussion_r1150861223