deployment: mediawiki/tools/codesniffer for Jenkins CI slaves

Will let anyone update MediaWiki codesniffer rules whenever a change is
merged in mediawiki/tools/codesniffer.  That is currently done using a
submodule on integration/jenkins.git.

bug: 57064
Change-Id: Ifdb423db1f662c249aa40e337b59c83d3dd98669