decouple credential metadata

[c2bo]

Closes #99

This is a bit different from what we discussed at last WG, thus marking it as draft for the time being.

[c2bo]

TODO: change all the examples

[Sakurann]

WG discussion:

• direction seems to make sense.

[sloops77]

@c2bo I'm not a fan of adding a credential_metadata claim. It's too generic sounding and makes me wonder why many other credential configuration isnt in there

Some options to consider:

1. rename the property to display_metadata, display_descriptor. Is there any purpose for this property than for wallet display?
2. type_metadata is an alternative to the above and shows alignment with sd-jwt-vc type metadata
3. nest claims inside of display, and update the sd-jwt-vc spec

[c2bo]

@c2bo I'm not a fan of adding a credential_metadata claim. It's too generic sounding and makes me wonder why many other credential configuration isnt in there

Some options to consider:

1. rename the property to display_metadata, display_descriptor. Is there any purpose for this property than for wallet display?
2. type_metadata is an alternative to the above and shows alignment with sd-jwt-vc type metadata
3. nest claims inside of display, and update the sd-jwt-vc spec

I thought about different names as well, but the main thing I wanted to make sure was that from the name it is clear that the "other" metadata is necessary before the Credential Request, whereas this is relevant during the lifetime of the credential. Right now we have mainly display information but there could be other metadata with the same lifecylce -> a more generic name made sense to me. More opinions on that topic?