FEATURE: Move to algolia search

[lwasser]

I setup an application that searched across the pyopensci.org domain. I want to now connect algolia to our theme (which the theme can support already).
I think we want to use the algolia docsearch rather than the jekyll algolia plugin as it's already setup under an open source license.

So the next step is to add the js and such to trigger algolia to work. We can then also add it to our sphinx books along with a consistent top bar nav that takes people back to our website if they want?