Add Yokozuna Docs (2.0)

This is a two-phase project. The first is to move the existing Legacy Search information into a parallel set of documents (prefix with `legacy-`, eg `legacy-search.md`). Then replace the existing search docs with new search information.

- [x] Using Search
- [x] Advanced Search
- [ ] Search Schema (move to advanced, out of reference... link to solr and code as reference)
- [ ] Configure Search