Add search functionality

[bmaupin]

Dependencies

• [x] #14 Better 404 handling

Minimal solution:

Some kind of text box that just redirects to google with site:https://bmaupin.github.io/wiki/ appended to the query

Ideal solution:

Auto filling JavaScript search box

• Use pages.json from #14
• It might be nice to have a popup that way we can show results instantly (https://docs.readthedocs.io/en/stable/index.html)

[bmaupin]

• https://blog.webjeda.com/instant-jekyll-search/
• https://github.com/christian-fei/Simple-Jekyll-Search/