[RFC] support for role names as the process_space in Looks

Recently I've been thinking a bit about how to improve the config format, so I'm going to open a few issues to spawn some discussions, relates to the recent v2 working group meeting discussion.

One thing I noticed this morning, is that it is not possible in v1 to use a role name for the process_space in a Look (running ociocheck fails as an example).

My specific use case was I wanted to specify in a generic way that client supplied LUTs 'client Look' should be applied in 'the client Look colour space', using the role as an indirection layer, which also helps with anybody reading the config, with understanding the intent.

I know there are limitations with this, when you have a requirement for multiple colour spaces, but I had another thought for that...

Beginne mit der Untersuchung der von ociocheck ausgeübten v1-Konfigurationsverarbeitung und konzentriere dich darauf, wie process_space für einen Look interpretiert wird. Vergleiche das aktuelle Verhalten mit der vorgeschlagenen Indirektion über Rollennamen und definiere das erforderliche Konfigurations- und Validierungsverhalten, um den Anwendungsfall zu unterstützen.

Vom Indexierungsmodell aus dem Issue-Text verfasst.