cmake,lib,base: Export obs-websocket-api as a target

[tytan652]

Description

Relies on:

• https://github.com/obsproject/obs-studio/pull/10100

This enables the installation of the header in the include directory by exporting it as an interface target

Motivation and Context

No more copy-pasting the header to use it

How Has This Been Tested?

Tested OS(s):

• Arch Linux

Windows and macOS headers needs to be checked

• Tested on Windows, --component Development adds the header

Types of changes

• Other Enhancement (anything not applicable to what is listed)

Checklist:

• [x] I have read the Contributing Guidelines.
• [x] All commit messages are properly formatted and commits squashed where appropriate.
• [x] My code is not on master or a release/* branch.
• [x] The code has been tested.
• [x] I have included updates to all appropriate documentation.

[tt2468]

Looks good to me, just curious if Pat has any comments on doing this

[tytan652]

This PR, the updated CMake of the obs-browser-api PR and the obs-studio PR that they rely on were based on a discussion I had with Pat about shipping those headets.

So for the 3 PRs, I'm waiting for Pat's feedback.