RFR: 1823: Mailing list bot should include link to comment on the Git forge

[Zhao Song]

This patch will add the ability to attach comment/reviewComment/review link to the email generated by mlbridge bot

The implementation for GitHub is straightforward, we can extract the URL for a specific comment or review from the JSON response using the `html_url` field and include it in the email. 

For GitLab, we will need to generate the URL using the `id` field in `note,` since GitLab does not provide an field like `html_url` in its JSON responses.

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Commit messages:
 - SKARA-1823

Changes: https://git.openjdk.org/skara/pull/1478/files
 Webrev: https://webrevs.openjdk.org/?repo=skara&pr=1478&range=00
  Issue: https://bugs.openjdk.org/browse/SKARA-1823
  Stats: 205 lines in 11 files changed: 182 ins; 0 del; 23 mod
  Patch: https://git.openjdk.org/skara/pull/1478.diff
  Fetch: git fetch https://git.openjdk.org/skara pull/1478/head:pull/1478

PR: https://git.openjdk.org/skara/pull/1478