config: add wiki links

main wiki link included with "about" and "user profiles". Sections with
a relevant page have a linked button next to their title when clicked.
Behaviour added by the "wiki_link" field in the "meta" section of a
config "section".

lang/admin/en-us.json

@@ -201,7 +201,8 @@
         "backupCreated": "Backup created",
         "backupCanBeFound": "The backup can be found on the server at {filepath}.",
         "backupCanDownload": "Alternatively, click below to download the backup.",
-        "wikiPage": "Wiki Page"
+        "wikiPage": "Wiki Page",
+        "wiki": "Wiki"
     },
     "notifications": {
         "pathCopied": "Full path copied to clipboard.",