Update ClientRequestMetadata to display client identity

This is dependent on buildgrid!1090.

This MR updates ClientRequestMetadata to display the full set of RequestMetadata fields, as well as client identity information. As part of this it includes a full REAPI proto update, and also contains some minor fixes to nearby code.

This rework also moves away from using cards for this metadata, as they frequently end up unbalanced and messy if any metadata fields are particularly long. The cards used in CommandMetadata are similarly removed, for the same reasons.