Technical debt/Unused config

For the script that detects unused variables in wmf-config, see https://gist.github.com/Krinkle/15be368abdbf918c8ef7a06cde011457.

Resolved items are removed in batches. See prior work at one, two, …

Results as of Thu 2019-07-11 17:59:54 -0800 with operations/mediawiki-config.git at 60caca698f16f7e100becf86db4497f786701b88:

Param	Filename	Component	Status
CentralAuthAutoNew	CommonSettings.php
CentralAuthUseSlaves	CommonSettings-labs.php CommonSettings.php
CirrusSearchEnableSearchLogging	CirrusSearch-labs.php CirrusSearch-production.php
ContentTranslationEventLogging	CommonSettings.php
DisableRollbackConfirmationFeature	InitialiseSettings.php
EnableBlockNoticeStats	InitialiseSettings.php
FlowMaintenanceMode	CommonSettings.php
GEHomepageMobileEnabled	InitialiseSettings-labs.php InitialiseSettings.php
LDAPLowerCaseUsernameScheme	wikitech.php
LDAPUseFetchedUsername	wikitech.php
NoticeFundraisingUrl	CommonSettings.php
NotificationSenderName	CommonSettings.php
OpenStackManagerLDAPProjectGroupBaseDN	wikitech.php
OpenStackManagerLDAPUseUidAsNamingAttribute	wikitech.php
OpenStackManagerPuppetDocBase	wikitech.php
OpenStackManagerPuppetOptions	wikitech.php
QuickSurveysRequireHttps	CommonSettings-labs.php
RelatedArticlesLoggingBucketSize	CommonSettings.php
RestrictionMethod	CommonSettings.php
TranslateClustersAndMirrors	CommonSettings.php
UseContributionTracking	CommonSettings.php InitialiseSettings.php
WBCSDefaultPrefixRescoreProfile	SearchSettingsForWikidata.php
WBCSEnableDispatchingQueryBuilder	SearchSettingsForSDC.php
WBCSFulltextSearchProfile	SearchSettingsForWikidata.php
WBCSFulltextSearchProfiles	SearchSettingsForWikidata.php
WBCSPrefixSearchProfiles	SearchSettingsForWikidata.php
WBCSRescoreFunctionChains	SearchSettingsForWikidata.php
WBCSRescoreProfiles	SearchSettingsForWikidata.php