RFR: SKARA-1096: New command and label for JEPs, similar to CSR [v10]

[Guoxiong Li]

> Hi all,
> 
> This patch implements the features about the `/jep` command and JEP bot. The detailed designs and discussions are listed at [1][2].
> 
> Thanks for taking the time to review.
> 
> Best Regards,
> -- Guoxiong
> 
> [1] https://mail.openjdk.java.net/pipermail/skara-dev/2021-December/005481.html
> [2] https://mail.openjdk.java.net/pipermail/skara-dev/2022-March/005770.html

Guoxiong Li has updated the pull request incrementally with two additional commits since the last revision:

 - Polish
 - Overload the handle method and revert the change of unrelated commands

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

Changes:
  - all: https://git.openjdk.java.net/skara/pull/1297/files
  - new: https://git.openjdk.java.net/skara/pull/1297/files/84a87bc4..ee84a2b9

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=skara&pr=1297&range=09
 - incr: https://webrevs.openjdk.java.net/?repo=skara&pr=1297&range=08-09

  Stats: 62 lines in 15 files changed: 22 ins; 15 del; 25 mod
  Patch: https://git.openjdk.java.net/skara/pull/1297.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/1297/head:pull/1297

PR: https://git.openjdk.java.net/skara/pull/1297