RFR: 1384: Cannot configure integrators for repositories in PullRequestBot [v2]

[Zhao Song]

> Now, `PullRequestBotFactory` could parse the config `integrators`.
> 
> Also fixed some whitespace issues in `PullRequestBotFactoryTest`

Zhao Song has updated the pull request incrementally with one additional commit since the last revision:

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

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Changes:
  - all: https://git.openjdk.org/skara/pull/1402/files
  - new: https://git.openjdk.org/skara/pull/1402/files/e4c60499..78ddbcdd

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=skara&pr=1402&range=01
 - incr: https://webrevs.openjdk.org/?repo=skara&pr=1402&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/skara/pull/1402.diff
  Fetch: git fetch https://git.openjdk.org/skara pull/1402/head:pull/1402

PR: https://git.openjdk.org/skara/pull/1402