RFC 45-2: Add protocol in Services API and enum functions in Outputs API

[tytan652]

Description

This PR is about the RFC 45.

Depends on:

• https://github.com/obsproject/obs-studio/pull/5104

Additions (those will be used in other parts of RFC 45 implementation):

• Adds get_protocol to services
• Add three enumeration functions:
  • obs_enum_output_protocols to enumerate protocols
  • obs_enum_output_protocols_prefixes to enumerate protocol prefixes
  • obs_enum_output_service_types to enumerate outputs with OBS_OUTPUT_SERVICE.

Motivation and Context

Part of the implementation of the RFC 45.

How Has This Been Tested?

Testing by logging enumeration functions outputs and through other part of RFC 45 implementation.

Types of changes

• New feature (non-breaking change which adds functionality)

Checklist:

• [x] My code has been run through clang-format.
• [x] I have read the contributing document.
• [x] My code is not on the master branch.
• [x] The code has been tested.
• [x] All commit messages are properly formatted and commits squashed where appropriate.
• [x] I have included updates to all appropriate documentation.