RFR: 2042: Allow bulk requests with /approval request command [v3]

[Zhao Song]

> As some users requested, we will allow bulk requests with `/approval` request command.
> 
> If an id is not specified in the `/approval` command, the bot will generate a maintainer approval request for all associated bugs.
> 
> This also applies to the `/approval cancel` command, which will cancel the maintainer approval request for all associated bugs.

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

  review comment

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

Changes:
  - all: https://git.openjdk.org/skara/pull/1565/files
  - new: https://git.openjdk.org/skara/pull/1565/files/29ad3fee..cec12170

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=skara&pr=1565&range=02
 - incr: https://webrevs.openjdk.org/?repo=skara&pr=1565&range=01-02

  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/skara/pull/1565.diff
  Fetch: git fetch https://git.openjdk.org/skara.git pull/1565/head:pull/1565

PR: https://git.openjdk.org/skara/pull/1565