Git files for labs branch

Change-Id: I7a383abaacb7f9bc48fc93323a3619f6f7b01106
labs: Create dummy jobs

Creates:
    mediawiki-core-lint
    mwext-FirstExtension-lint
    mwext-SecondExtension-lint

Change-Id: I4714397e89d4bd3b30fe9af966f5537e3c29f8a6
Dump of Zuul env is now a macro

Change-Id: I8c321720fb1dfa2069d998f10096565b954fcf93
integration-mediawiki based on Zuul cloner

Creates:
    integration-many-mw-exts
    integration-with-mediawiki

Change-Id: I2670cbe8e1a54e0025a7450b6b12b8199cfd9b7b
Merge branch 'gerrit/attic/jjb-config/labs' into labs

Migrated the jjb jobs.yaml file under /jjb/ to reflect the changes made
in the master branch.

Conflicts:
	.gitignore
	.gitreview

Change-Id: I77466cd6689521ab1cf7024017aee485c75f0a7b