Update the search feature so it fits organization needs rather than simply uses Wagtail defaults

[keeganland]

Rudimentary default-behaviour search in wagtail can occur if one simply calls .search() on a queryset of Page objects. The site does not currently have any more robust search than this.

Behaviour of search, however, is very robustly configurable and can be improved beyond defaults. See wagtail documentation thereof: https://docs.wagtail.org/en/stable/topics/search/index.html

Task should be divided into three prongs: 1) ensuring the site indexed for search 2) adjusting the results returned by the search function itself 3) choosing and installing "search backends" that support search

Certain important database changes may be important prior to addressing this issue, see issue #860. Particularly, PostgreSQL is sometimes said to have better support for search-related features in Django than MySQL.

[keeganland]

(minor note on relation to other issue: I am not sure I understand the different db features well enough to say how strong this dependency is... I used to think no sort of search would be possible with MySQL, then learned it clearly is but behaves funny. Stating in precise terms what's would be missing without PostgreSQL is difficult, and there's the risk that it will be a lot. This leaves the exact scope of the problems that will be encountered in doing any search changes ambiguous.)