Reduce size of wiki entrypoint

[LeoMcA]

Currently the wiki entrypoint is rather a lot larger than it needs to be, because it includes codes and (especially) imports which are only used on the editing/contributor side of the wiki.

We should split that code and those imports into a separate entrypoint to minimise the amount of code end-users need to load to view wiki articles.

[LeoMcA]

https://github.com/mozilla/kitsune/pull/4980

[LeoMcA]

QA: regression testing of KB documents and KB editing would be great here

[mirunacurtean]

Regression tests have included the following actions: Edit article:

• add new content, new keyword, new summary
• preview changes
• preview content
• Submit changes
• Cancel review
• Defer Revision
• Compare revisions
• Delete revision
• approve own revision / approve other user's revision
• approve revision for Localization
• translate and approve translation of article
• edit contributors / document contributors list being updated successfully after contribution has been approved

@LeoMcA However, I cannot find article in search (either in English or German locale): https://support.allizom.org/en-US/kb/forum-response-userchromecss-warning/show_translations

[LeoMcA]

@LeoMcA However, I cannot find article in search (either in English or German locale): https://support.allizom.org/en-US/kb/forum-response-userchromecss-warning/show_translations

Looks like it's in the canned responses category, so won't appear in search. I tested adding a new article and it appears in search, after a short delay