feat(reva): Pass the multi-tenancy flag to reva services

This allows to pass the multi-tenant enablement flag as a shared config
option to the reva service. This needs to be done for all reva services
since it ends up in a global variable in reva that is only initialized
once, by the service that is the first to parse its config.
See https://github.com/opencloud-eu/opencloud/issues/1563 for details.

services/ocm/pkg/revaconfig/config.go

@@ -25,9 +25,10 @@ func OCMConfigFromStruct(cfg *config.Config, logger log.Logger) map[string]inter
 
 	return map[string]interface{}{
 		"shared": map[string]interface{}{
-			"jwt_secret":          cfg.TokenManager.JWTSecret,
-			"gatewaysvc":          cfg.Reva.Address, // Todo or address?
-			"grpc_client_options": cfg.Reva.GetGRPCClientConfig(),
+			"jwt_secret":           cfg.TokenManager.JWTSecret,
+			"gatewaysvc":           cfg.Reva.Address, // Todo or address?
+			"grpc_client_options":  cfg.Reva.GetGRPCClientConfig(),
+			"multi_tenant_enabled": cfg.Commons.MultiTenantEnabled,
 		},
 		"http": map[string]interface{}{
 			"network": cfg.HTTP.Protocol,