Initial Profiles proposal

[dgovil]

Description of Proposal

This PR proposes the addition of profiles as metadata to USD documents.
Profiles are short, structured descriptions of potentially non-standard features
used within the stage such that a runtime or human can know of their existence ahead of time.

Profiles are not meant to change runtime parsing behaviour, and are essentially just
informational hints.

A proposed example would be:

(
    profile = {
        string name = "org.openusd.core"
        string version = "1.2.3"
        dictionary compatibility = {
            string com.apple.realitykit = "4.3.2"
        }
        dictionary required = {
            dictionary fileFormats = {
                string org.aom.vvm = "1.0.0"
            }
        }
        dictionary optional = {
            dictionary schemas = {
                string com.apple.realitykit.components = "1.0.0"
            }
        }
    }
)

Link to Rendered Proposal

Contributing

• I agree to and accept the Supplemental Terms.

[meshula]

Approved to merge for discussion as draft.