obs-ffmpeg: Replace external/AMF folder by obs-deps headers

[tytan652]

Description

Depends on:

• https://github.com/obsproject/obs-deps/pull/152

Remove external/AMF headers folder from obs-ffmpeg and use obs-deps headers.

Difference between upstream and "external":

• "external" have outdated code compared to 1.4.28 from upstream
• This enum value that is not present upstream and is unused in OBS Studio whole repo (the header itself is not used), so it's removal is seamless.

How ?: I pasted 1.4.28 over our "external" version and each diff (except the enum value) happen to be new code because if I blame upstream code and check the prior code, the prior code match "external".

And AMF_HQ_SCALER_ALGORITHM_FSR1_1 looks completely unused when I search in OBS Studio repo locally.

Motivation and Context

Cleanup

How Has This Been Tested?

Build on my Windows VM and on CI.

Will may need ~~NVENC and~~ AMF encoder tests.

Types of changes

• Code cleanup (non-breaking change which makes code smaller or more readable)

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.
• [ ] 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.

[tytan652]

Restored Nvidia's headers to not conflict with #7430.

And until obs-deps can have up to date Nvidia headers, the external folder will be kept for Nvenc encoders.

[tytan652]

Note: Put as draft until AMD release their updated headers with AV1.

[tytan652]

We can use AMF 1.4.28, but kept as draft until this https://github.com/obsproject/obs-deps/pull/152 is merged and obs-deps have a new release.

[tytan652]

Also I added a finder for AMF with version.

[tytan652]

Fixed AMF_VERSION_ values not being set properly. (So just nitpicking)

[RytoEX]

Is the Finder for all platforms, or just some platforms? I was able to build just the first commit on Windows seemingly fine. Does the Finder need to be introduced first, or would that cause problems?

[tytan652]

Is the Finder for all platforms, or just some platforms? I was able to build just the first commit on Windows seemingly fine. Does the Finder need to be introduced first, or would that cause problems?

Also answered off-thread, the finder is not required because the required include directory is already added. But adding it allows to check if AMF is really present and check the version.