POC for mutating realm.json

[UnicornChance]

Problem:

At the moment the only way to modify or change the realm is changing the configuration here. When someone wants to bring their own realm.json they have to go through the whole process of building the image.

We can't provide overrides for everything and also doesn't make sense to make default things for everyone when only a small group would otherwise use it. Providing easier realm.json configuration would allow easier individual customization.

Outcomes:

• Can we find a way to allow for someone to provide a realm without builidng the identity-config image?
• Or mutate a realm.json during the identity-config image creation?
• Donk-esque?