IAM: Protect external service accounts frontend list page (#77834)

* Add `isExternal` property to frontend model

* Remove enabled and token buttons for external SA

* Replace trash icon for lock icon for external SA

* Block the role picker for external SA

* Filter SA list using the external filter

* Add only external filter at backend

---------

Co-authored-by: Gabriel MABILLE <gamab@users.noreply.github.com>

pkg/services/serviceaccounts/models.go

@@ -85,7 +85,7 @@ type ServiceAccountDTO struct {
 	// example: false
 	IsDisabled bool `json:"isDisabled" xorm:"is_disabled"`
 	// example: false
-	IsManaged bool `json:"isManaged,omitempty" xorm:"-"`
+	IsExternal bool `json:"isExternal,omitempty" xorm:"-"`
 	// example: Viewer
 	Role string `json:"role" xorm:"role"`
 	// example: 0
@@ -157,7 +157,7 @@ type ServiceAccountProfileDTO struct {
 	// example: []
 	Teams []string `json:"teams" xorm:"-"`
 	// example: false
-	IsManaged bool `json:"isManaged,omitempty" xorm:"-"`
+	IsExternal bool `json:"isExternal,omitempty" xorm:"-"`
 
 	Tokens        int64           `json:"tokens,omitempty"`
 	AccessControl map[string]bool `json:"accessControl,omitempty" xorm:"-"`