RFR: 1199: Enforce maintainer approval in JBS before allowing to integrate backports into updates projects [v5]

[Zhao Song]

> As Erik said in the description of this issue, currently, this issue only cares about tracking approval labels in the related bugs.
> 
> If a repository is set up with the "approval" configuration, pull requests in that repository will require the maintainer's approval in JBS. Otherwise, the pull request will not be considered ready. 
> 
> Erik has also provided a design outlining how to configure the "approval" for a repository.
> 
> 
> The simple case, where the labels are the same for every branch in a repository: 
> 
> "approval": { 
>   "request": "jdk17u-fix-request", 
>   "approved": "jdk17u-fix-yes", 
>   "rejected": "jdk17u-fix-no", 
> } 
> 
> To reduce the need for changing multiple strings when copying a configuration for a new repository, there is an optional "prefix" field: 
> 
> "approval": { 
>   "prefix": "jdk17u-fix-", 
>   "request": "request", 
>   "approved": "yes", 
>   "rejected": "no", 
> } 
> 
> When there are multiple branches with different labels, having the prefix set per branch can help reduce the size of the configuration significantly: 
> 
> "approval": { 
>   "request": "-critical-request", 
>   "approved": "-critical-approved", 
>   "rejected": "-critical-rejected", 
>   "branches": [ 
>     "jdk20\.0\.1": { "prefix": "CPU23_04" } 
>   ] 
> }

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

 - fix test
 - fix test
 - update

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

Changes:
  - all: https://git.openjdk.org/skara/pull/1537/files
  - new: https://git.openjdk.org/skara/pull/1537/files/bc652f24..e55acd54

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=skara&pr=1537&range=04
 - incr: https://webrevs.openjdk.org/?repo=skara&pr=1537&range=03-04

  Stats: 61 lines in 6 files changed: 25 ins; 24 del; 12 mod
  Patch: https://git.openjdk.org/skara/pull/1537.diff
  Fetch: git fetch https://git.openjdk.org/skara.git pull/1537/head:pull/1537

PR: https://git.openjdk.org/skara/pull/1537