[cmake] pass vaapi and vdpau options to internal ffmpeg

[wsnipex]

When building non-depends with internal ffmpeg we currently hardcode ffmpeg options.
This PR allows to at least disable vaapi and vdpau in ffmpeg.

Description

Motivation and Context

building with internal ffmpeg fails when vaapi or vdpau is disabled and the needed libs are missing, or ffmpeg still builds with support for both hw accels.

How Has This Been Tested?

quick build test on linux.
I'm a little bit wary about the reordering of dependency checking, so this needs some testing

Screenshots (if appropriate):

Types of change

• Bug fix (non-breaking change which fixes an issue)
• Improvement (non-breaking change which improves existing functionality)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the Code guidelines of this project
• My change requires a change to the documentation, either Doxygen or wiki
• I have updated the documentation accordingly
• I have read the CONTRIBUTING document
• I have added tests to cover my change
• All new and existing tests passed

[Rechi]

The ccache workaround can now be removed too.

[wsnipex]

removed the ccache workaround.
I'm thinking that it sometimes might be useful to directly pass ffmpeg options (e.g. to build the ffmpeg binary or various optimizations) as well. Wouldn't be difficult to add here. Opinions?

[wsnipex]

jenkins build this please