Reorganize collections to allow them to be split across client/server

Right now, the collection code is defined in 'both' directory. This, by naming convention, implies that the code should run on both client and server. However, there are some aspects of collections, such as indexes, that only need to be defined on the server.

# Task
- reorganize collection data to allow it to be explicitly split between client and server
- break out parts of collection into explicit files, such as permissions, schema, etc

Related task: #259

Start by inspecting the collection code in the `both` directory and read related issue #259 for context. Map the existing collection data, including permissions, schema, and indexes, then reorganize it so client- and server-specific parts are explicit and separately located.

Written by the indexing model from the issue text.