Spawned out of T186062
The problem: Many config variables are shipped from MobileFrontend unnecessarily to desktop Vector. They are needed by Minerva operating in both desktop and mobile mode.
These are:
*wgMFMobileFormatterHeadings
* wgMFSearchAPIParams
* wgMFQueryPropModules
* wgMFSearchGenerator
* wgMFThumbnailSizes
* wgMFEditorOptions
* wgMFUsePreferredEditor
* wgMFLicense
* wgMFSchemaSearchSampleRate
* wgMFExperiments
* wgMFEnableJSConsoleRecruitment
* wgMFDeviceWidthTablet
* wgMFCollapseSectionsByDefault
* wgMFContentProviderScriptPath
* wgMFIsPageContentModelEditable
* wgMFEnableFontChanger
* wgMFDisplayWikibaseDescriptions
= Developer notes
[] wgMFIsPageContentModelEditable is used by mobile.init so only should be loaded on mobile pages. Moving this inside a $context->shouldDisplayMobileView()
[] wgMFEnableFontChanger is only used by SpecialMobileOptions so should be moved there
[] The rest, with the exception of wgMFDisplayWikibaseDescriptions can be easily be moved to ResourceLoader as that requires knowledge of the current user. Will defer to Timo if there is a solution for this specific config variable.
= Acceptance criteria
With the exception of '''wgMFDisplayWikibaseDescriptions'''
[] wgMF config variables DO NOT show up on desktop Vector
[] wgMF config variables show up on mobile Vector (https://en.m.wikipedia.org?useskin=vector)
[] wgMF config variables show up on mobile Timeless (https://en.m.wikipedia.org?useskin=vector)
[] wgMF config variables show up on desktop Minerva (https://en.wikipedia.org?useskin=minerva)
[] wgMF config variables show up on mobile Minerva (https://en.m.wikipedia.org?useskin=vector)
= Sign off steps
With the exception of '''wgMFDisplayWikibaseDescriptions''' confirm no MobileFrontend variables on http://localhost:8888/w/index.php/Spain?useskin=vector&useformat=desktop
```
Object.keys(mw.config.values).filter((key)=>key.indexOf('MF' ) > -1)
```