Improve loading configs

[melegiul]

In the moment the custom required actions assume there exists an authenticator config object with the alias "sms-2fa".
Instead of loading the config by this predefined alias it should be loaded either from the database (with arbitrary alias) or loaded from keycloaks globale settings (see #20 (comment) and following)

[svenseeberg]

It may be possible to set custom realm attributes with the kcadm.sh tool:

kcadm.sh update -r myrealm -s sms-2fa-default-api-provider=sms-2fa-foobar

if that does not work, it would be possible to set this manually in the database in the realm_attribute table, which has the following columns: name, realm_id, value. As in:

INSERT INTO realm_attribute (realm_id, name, value) VALUES ('REALM_UUID', 'sms-2fa-default-api-provider', 'sms-2fa-foobar');

[melegiul]

Each RequiredActionFactory and AuthenticatorFactory overrides this method:

@Override
    public void init(Config.Scope config) {

    }

Here it says, that this config is loaded from a file called keycloak_server.json, but I didn't tried this yet: https://github.com/keycloak/keycloak/blob/48266fa48fbd6ea4ec8d07df8e990850be6ba9a3/server-spi/src/main/java/org/keycloak/provider/ProviderFactory.java#L39

[melegiul]

Passing configs to spi providers actually works like this:

1. Run keycloak and pass configs to CLI command e.g. bin/kc.sh start-dev --spi-required-action-mobile_number_config-code-length="6" (https://www.keycloak.org/server/configuration-provider)
2. Read config in corresponding factory init(Config.Scope config) { config.getInt("code-length", default); }

Downside is, that we have many configs to pass.

[svenseeberg]

Downside is, that we have many configs to pass.

I guess there must be a way to put everything into one config file? That would be a nice solution. Then we can remove the config from the single authentication flows. The current solution feels a bit hacky.

There is a discussion about configuring providers: keycloak/keycloak#10311