Better handle OPDS server root content types. (PP-1959)

[tdilauro]

Description

• Loosens content media type checking from exact string match to matching on a type prefix and a minimal set of type directives.
• Adds a normalized media type class that can be applied to other URL matching in the future.
• Adds some test cases to cover some that were previously missing.

NB: Note that some linter checks failed. The linter was changing some things that were unrelated to this PR, so I removed them for now. Once this PR is reviewed, I'll add the changes from the linter. I have added these changes.

Motivation and Context

Palace Manager #2142 introduced a change in the feed content types and this PR is aimed at catching up with those changes.

[Jira PP-1959]

How Has This Been Tested?

• Tests pass locally.
• CI tests for associated branch pass.

Checklist

• N/A I have updated the documentation accordingly.
• All new and existing tests passed.

[dbernstein]

Looks good 🚀 🐎 🐰