Standardise on MinervaNeue's skin name (minerva)

We will standardise on the key "minerva" and the styles
in MediaWiki:Minerva.css for desktop since this is what is
used for mobile. The name will however appear as MinervaNeue
to be consistent with the skin repo name (not the code).

Please merge I5fdb21243e0b599b07aa228107fd4b8c306c696c
shortly after merging this to remove the remaining logic
relating to this from MobileFrontend as otherwise two skins
will appear in user preferences.

Any existing users of MinervaNeue (key minervaneue on desktop)
will be thrown back into the Vector skin and will need to opt
into the MinervaNeue skin again. This is a minor disruption
given the low amount of users and instability of the skin.

Bug: T171644
Change-Id: Ieffb6334168047dcf05dcb60281865ab47056dc0

i18n/en.json

@@ -2,7 +2,6 @@
 	"@metadata": {
 		"authors": []
 	},
-	"skinname-minervaneue": "MinervaNeue",
 	"minerva-last-modified-date": "Last edited on $1, at $2",
 	"minerva-talk-add-topic": "Add discussion",
 	"mobile-frontend-console-recruit": "\\o/ Hey! This is open source software and we need volunteers to help us build this thing, make it better and fix any bugs that you might be seeing in this JavaScript console!\n\nYou can find our backlog @ https://phabricator.wikimedia.org/project/profile/67/",
@@ -54,6 +53,6 @@
 	"mobile-frontend-user-page-member-since": "{{GENDER:$2|Joined}} $1",
 	"mobile-frontend-user-page-talk": "Talk",
 	"mobile-frontend-user-page-uploads": "Uploads",
-	"skinname-minerva": "Minerva",
+	"skinname-minerva": "MinervaNeue",
 	"minerva-skin-desc": "A responsive mobile first skin"
 }

i18n/qqq.json

@@ -11,7 +11,7 @@
 			"Umherirrender"
 		]
 	},
-	"skinname-minervaneue": "The skin name for MinervaNeue.",
+	"skinname-minerva": "The skin name for MinervaNeue.",
 	"minerva-last-modified-date": "Text that displays the date the page was last modified. Parameters:\n* $1 - date\n* $2 - time\n{{Related|Mobile-frontend-last-modified}}",
 	"minerva-talk-add-topic": "Label for button which shows at bottom of talk pages in mobile view prompting addition of topic",
 	"mobile-frontend-console-recruit": "Message that is displayed in the JavaScript console aimed at developers in an attempt to recruit volunteers. The \\o/ emoticon is a man with his arms in the air with the purpose of drawing attention to the message. If this doesn't translate into the destination language feel free to omit it or use something more applicable.",
@@ -63,6 +63,5 @@
 	"mobile-frontend-user-page-member-since": "Message below the heading. $1 is the user registration date. $2 is the gender associated with the user account.",
 	"mobile-frontend-user-page-talk": "Text of the link to the user's talk page\n{{Identical|Talk}}",
 	"mobile-frontend-user-page-uploads": "Text of the link to the user's uploads page\n{{Identical|Upload}}",
-	"skinname-minerva": "{{optional}}",
 	"minerva-skin-desc": "{{desc|name=Minerva Neue|url=https://www.mediawiki.org/wiki/Skin:Minerva_Neue|what=skin}}"
 }

skin.json

@@ -480,8 +480,7 @@
 		}
 	},
 	"ValidSkinNames": {
-		"minervaneue": "MinervaNeue",
-		"minerva": "Minerva"
+		"minerva": "MinervaNeue"
 	},
 	"author": [],
 	"config": {