Move realms, clients, groups, roles, clientscopes into legacy module

- Introduces Datastore SPI for isolating data store methods
- Introduces implementation of the datastore for legacy storage
- Updates DefaultKeycloakSession to leverage Datastore SPI instead
  of direct creating of area providers by the session

 src/main/java/org/keycloak/protocol/cas/utils/RedirectUtils.java

@@ -80,7 +80,7 @@
    @Deprecated
    private static Set<String> getValidateRedirectUris(KeycloakSession session) {
        RealmModel realm = session.getContext().getRealm();
        return session.clientStorageManager().getAllRedirectUrisOfEnabledClients(realm).entrySet().stream()
        return session.clients().getAllRedirectUrisOfEnabledClients(realm).entrySet().stream()
          .filter(me -> me.getKey().isEnabled() && OIDCLoginProtocol.LOGIN_PROTOCOL.equals(me.getKey().getProtocol()) && !me.getKey().isBearerOnly() && (me.getKey().isStandardFlowEnabled() || me.getKey().isImplicitFlowEnabled()))
          .map(me -> resolveValidRedirects(session, me.getKey().getRootUrl(), me.getValue()))
          .flatMap(Collection::stream)