Add partial Wikidot support

[in1tiate]

Doesn't support wikis using third party search components like the SCP Wiki's Crom. Those will need special support on a case-by-case basis.

Example formatting for a Wikidot wiki using this setup. Note that this particular wiki's search function appears to be offline, however Wikidot wikis all use the same default search page (unless using the aforementioned third party components)

  {
    "id": "en-darksouls-fandom",
    "origins_label": "Dark Souls Fandom Wiki",
    "origins": [
      {
        "origin": "Dark Souls Fandom Wiki",
        "origin_base_url": "darksouls.fandom.com",
        "origin_content_path": "/wiki/",
        "origin_main_page": "Dark_Souls_Wiki"
      }
    ],
    "destination": "Dark Souls Wiki",
    "destination_base_url": "darksouls.wikidot.com",
    "destination_platform": "wikidot",
    "destination_icon": "darksouls.png",
    "destination_main_page": "index.php",
    "destination_search_path": "/search:site/q/"
  },

[SnorlaxMonster]

As I mentioned in #485 , the alternative Wikidot search function search:main is currently functional (although I've only seen AQW Wiki use it). It works with the path structure added by this commit, so I think it could be worthwhile merging this commit even just to support AQW Wiki.

I looked into SCP Wiki's search:crom, but as far as I can tell, it's not possible to access it via URL. But there isn't a non-independent wiki to redirect to SCP Wikis, and I haven't seen Wikidot wikis outside of the SCP wikis that use search:crom, so that shouldn't be a problem.

[in1tiate]

Converted to draft - seems like there are structural changes that will require extra effort to rebase onto

[SnorlaxMonster]

I believe this is superseded by #738. It's now possible to add redirects to certain Wikidot wikis (as I have done in #755).