Make new bug link in flakiness dashboard configurable

Make new bug link in flakiness dashboard configurable
https://bugs.webkit.org/show_bug.cgi?id=123386

Reviewed by Alexey Proskuryakov.

* config.json: Added Bugzilla as the default destination for new bugs.
* public/api/manifest.php: Include newBugLinks in the manifest.
* public/index.html:
(TestResultsView): Initialize _newBugLinks.
(TestResultsView.setNewBugLinks): Added.
(TestResultsView._populateTestPane):
(TestResultsView._createTestResultRow): Replaced the hard-coded Bugzilla URL by the code
to generate hyper-links based on _newBugLinks. Also added a nullity check while formatting
revision checks so that we don't blow up when some build doesn't contain all revision info.
(TestResultsView._populateBuilderPane):

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@158095 268f45cc-cd09-0410-ab3c-d52691b4dbfc