[Feature] Support baked in list of default avatars

[techanon]

Is your feature request related to a problem?

Currently no easy way to include custom avatars as default avatars for a custom build of basis.

Describe your preferred solution

I'd like to see some mechanism where we can provide a list of pre-built avatar Asset Definition (Bundle+Meta+key) and include them into the build without having them be explicitly in the project itself.
Eg: A club scene application wishes to provide some pre-built optimized avatars that have some special effects on them (like audiolink, glowstick toggles or whatever), but it wants to update the content of those avatars separate from updating the entire application itself. These avatars would be loaded into the application's avatar listing as always available "application-provided" avatars.

Describe any considered alternatives

This might be able to be handled by some other theoretical change in the future (eg: adding the ability to add in a list of avatar asset definitions in bulk), but for now this is the minimum I'd like to see.

Additional Context

No response

[dooly123]

this has existed for a while