refactor: reorganize internal/search

Created by: rvantonder

This only moves things around and updates imports. See individual commits:

• move the files in /search/search/ into internal/search
• rename search_types.go to types.go
• rename search.go to args.go, since search.go doesn't really give an idea what this file is about, and it mostly contains type Args. The types in this file are a good fit for types.go, later.
• move search/query to internal/query. The idea is that this removes deeper nesting under internal/search, and query is already a concept for automation and in other places, so making it it's own toplevel package/directory seems reasonable