meson: Add all, all_free (default) options for video-codecs option
What does this MR do and why?
What: Adds two new possible values to the -Dvideo-codecs build option: 'all' and 'all_free'
Why: 'all' is added for convenience, 'all_free' is added as default value to restore the behavior previous to 7b22dd8b where such codecs were enabled by default.
Fixes: 7b22dd8b ("meson: add vp9 and av1 codec support options")
This PR is a result of discussions at !26223 (comment 2176484) cc @jenatali @leoliu @FireBurn @FabioPedretti @eric
Edited by Sil Vilerino