RFR: 1851: Fold CSR bot into PR bot [v4]

[Zhao Song]

> In this patch, the whole csr bot module is removed. 
> 
> Original CSRPullRequestBot is deleted. The functionality of this bot has been moved to `CheckRun`.
> 
> Original CSRIssueBot has been moved to pr bot module. PullRequestBotFactory would generate a CSRIssueBot for every configured Issue project.

Zhao Song has updated the pull request incrementally with three additional commits since the last revision:

 - Update bots/pr/src/main/java/org/openjdk/skara/bots/pr/PullRequestWorkItem.java
   
   Co-authored-by: Erik Joelsson <37597443+erikj79 at users.noreply.github.com>
 - Update bots/pr/src/main/java/org/openjdk/skara/bots/pr/PullRequestWorkItem.java
   
   Co-authored-by: Erik Joelsson <37597443+erikj79 at users.noreply.github.com>
 - Update bots/pr/src/main/java/org/openjdk/skara/bots/pr/PullRequestWorkItem.java
   
   Co-authored-by: Erik Joelsson <37597443+erikj79 at users.noreply.github.com>

-------------

Changes:
  - all: https://git.openjdk.org/skara/pull/1492/files
  - new: https://git.openjdk.org/skara/pull/1492/files/f06cf10e..c5990274

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=skara&pr=1492&range=03
 - incr: https://webrevs.openjdk.org/?repo=skara&pr=1492&range=02-03

  Stats: 3 lines in 1 file changed: 0 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/skara/pull/1492.diff
  Fetch: git fetch https://git.openjdk.org/skara.git pull/1492/head:pull/1492

PR: https://git.openjdk.org/skara/pull/1492