[keycloak-dev] Provider config framework

[Stian Thorgersen]

Once 1.0.final is released I'd like to work on adding a generic mechanism to configure SPI providers to keycloak-server.json, the model, and admin console.

The basic idea is to have a "providers" section on the admin console. There will be a drop-down to select the SPI you want to configure (audit, social, email, etc.). Once you've selected the SPI it will be possible to select what providers are active, and to be able to configure individual providers. Some SPIs/providers will let you specify a global configuration for the server, others a config for a realm, and maybe also a combination.

Then we should add a ProvideConfigModel to the model, which will replace a fair amount of stuff on RealmModel, such as smtp-settings and social-settings.

The benefits includes:

* Ability to config custom providers through console
* Simplified model / less crap on RealmModel
* Global provider config with realm override