Get rid of duplicated Reva config struct

Consolidate all services to use the Reva config struct for the shared package.
This works because all services (except 'notifications', 'thumbnails' and
'webdav') where using the same config keys and environment variables for
setting the reva gateway.

services/frontend/pkg/config/config.go

@@ -20,7 +20,7 @@ type Config struct {
 	TransferSecret string `yaml:"transfer_secret" env:"STORAGE_TRANSFER_SECRET" desc:"Transfer secret for signing file up- and download requests."`
 
 	TokenManager      *TokenManager `yaml:"token_manager"`
-	Reva              *Reva         `yaml:"reva"`
+	Reva              *shared.Reva  `yaml:"reva"`
 	MachineAuthAPIKey string        `yaml:"machine_auth_api_key" env:"OCIS_MACHINE_AUTH_API_KEY;FRONTEND_MACHINE_AUTH_API_KEY" desc:"Machine auth API key used to validate internal requests necessary to access resources from other services."`
 
 	SkipUserGroupsInToken bool `yaml:"skip_user_groups_in_token" env:"FRONTEND_SKIP_USER_GROUPS_IN_TOKEN" desc:"Disables the loading of user's group memberships from the reva access token."`

services/frontend/pkg/config/defaults/defaultconfig.go

@@ -1,6 +1,7 @@
 package defaults
 
 import (
+	"github.com/owncloud/ocis/v2/ocis-pkg/shared"
 	"github.com/owncloud/ocis/v2/services/frontend/pkg/config"
 )
 
@@ -28,7 +29,7 @@ func DefaultConfig() *config.Config {
 		Service: config.Service{
 			Name: "frontend",
 		},
-		Reva: &config.Reva{
+		Reva: &shared.Reva{
 			Address: "127.0.0.1:9142",
 		},
 		PublicURL:                "https://localhost:9200",
@@ -97,11 +98,11 @@ func EnsureDefaults(cfg *config.Config) {
 	}
 
 	if cfg.Reva == nil && cfg.Commons != nil && cfg.Commons.Reva != nil {
-		cfg.Reva = &config.Reva{
+		cfg.Reva = &shared.Reva{
 			Address: cfg.Commons.Reva.Address,
 		}
 	} else if cfg.Reva == nil {
-		cfg.Reva = &config.Reva{}
+		cfg.Reva = &shared.Reva{}
 	}
 
 	if cfg.TokenManager == nil && cfg.Commons != nil && cfg.Commons.TokenManager != nil {

services/frontend/pkg/config/reva.go

@@ -1,10 +1,5 @@
 package config
 
-// Reva defines all available REVA configuration.
-type Reva struct {
-	Address string `yaml:"address" env:"REVA_GATEWAY" desc:"The CS3 gateway endpoint."`
-}
-
 // TokenManager is the config for using the reva token manager
 type TokenManager struct {
 	JWTSecret string `yaml:"jwt_secret" env:"OCIS_JWT_SECRET;FRONTEND_JWT_SECRET" desc:"The secret to mint and validate jwt tokens."`