RFR: bot: add Bot.name and WorkItem.botName

[Erik Helin]

Hi all,

please review this patch that adds the methods `Bot.name` and `WorkItem.botName`. These methods are useful when adding metrics to code that deals with Bots and WorkItems (one often wants to create a `"bot"` label). I opted to add `static final` variables to the factories to ensure that names ending up as label values matches the names in the configuration files.

Thanks,
Erik

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

Commit messages:
 - bot: add Bot.name and WorkItem.botName

Changes: https://git.openjdk.java.net/skara/pull/1151/files
 Webrev: https://webrevs.openjdk.java.net/?repo=skara&pr=1151&range=00
  Stats: 279 lines in 53 files changed: 263 ins; 0 del; 16 mod
  Patch: https://git.openjdk.java.net/skara/pull/1151.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/1151/head:pull/1151

PR: https://git.openjdk.java.net/skara/pull/1151