RFR: Refactor notifier bot constructors

[Robin Westberg]

Hi all,

Please review this refactoring change that changes a few multi-argument-constructors into builders instead.

Best regards,
Robin

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Commits:
 - 2281f3c0: Builderify IssueUpdater
 - 0d1c76f6: Builderify MailingListUpdater
 - 5697a8c4: Fix unnecessary use of pattern
 - 8fa3e280: Builderify notify bot

Changes: https://git.openjdk.java.net/skara/pull/440/files
 Webrev: https://webrevs.openjdk.java.net/skara/440/webrev.00
  Stats: 773 lines in 13 files changed: 618 ins; 23 del; 132 mod
  Patch: https://git.openjdk.java.net/skara/pull/440.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/440/head:pull/440

PR: https://git.openjdk.java.net/skara/pull/440