RFR: Separate the various notifiers into their own packages

[Robin Westberg]

Hi all,

Please review this refactoring change that moves the various notifiers into their own packages, and moves the
configuration parsing into the respective package.

Best regards,
Robin

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Commit messages:
 - Separate the various notifiers into their packages

Changes: https://git.openjdk.java.net/skara/pull/631/files
 Webrev: https://webrevs.openjdk.java.net/skara/631/webrev.00
  Stats: 5930 lines in 31 files changed: 2803 ins; 3091 del; 36 mod
  Patch: https://git.openjdk.java.net/skara/pull/631.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/631/head:pull/631

PR: https://git.openjdk.java.net/skara/pull/631