feat: path-based locations

[mmalenic]

Closes #281
Depends on #284

Features

• Add a simple path-based way to writing location lists that includes file://, s3:// or http(s)://.
  *The first part of the location determines the storage, and everything in the path after determines the prefix which matches on ids. For example, s3://bucket/prefix says to find files in bucket when the request also contains the prefix - /reads/prefix/.
  • Locations can be specified as either a single location, or a list of locations with [].
  • The regex-style of specifying locations is still available. Config that is considered "advanced" is separated into a module, which is reflected in the docs.
• Paths are joined with Pathbuf rather than string formating, so config values like file://data/path and file://data/path/ are equivalent.

Docs

• Re-worked docs to include simplified locations first, with "advanced" config included later.