RFR: git-webrev: create links for bug ids in commit messages

[Erik Helin]

Hi all,

please review this patch that creates links to
[JBS](https://bugs.openjdk.java.net) for issue id:s in commit messages. This
patch also creates a link to the upstream revision if possible. Finally I also
updated some of the titles to match `webrev.ksh`.

The reason for not using the types `IssueProject` and `PullRequest` is that
`webrev.ksh` has traditionally never required a network connection. The bots
however are free to do so and can therefore provide better implementations for
`issueLinker` and `commitLinker`. This work will be done in a follow-up patch.

Testing:
- `make test` passes on Linux x64
- Manual testing of `git-webrev`

Thanks,
Erik

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

Commits:
 - e7683755: git-webrev: create links for bug ids in commit messages

Changes: https://git.openjdk.java.net/skara/pull/444/files
 Webrev: https://webrevs.openjdk.java.net/skara/444/webrev.00
  Stats: 94 lines in 5 files changed: 76 ins; 1 del; 17 mod
  Patch: https://git.openjdk.java.net/skara/pull/444.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/444/head:pull/444

PR: https://git.openjdk.java.net/skara/pull/444