[Feature request] change the license of some video (or add a license field in the CfP form)

[tai271828]

According to the discussion in 2021, some video may not fit into the current C.C. license. We may change them back to the default Youtube license.

For more context, see (private) https://discord.com/channels/752904426057892052/917259021369622568/917306612098682931

[uranusjr]

A somewhat related feature request is to add a license field in the CfP form, and add configuration in the video publisher to set license on a per-video basis (instead of globally).