Service Accounts: Display name to ID (#46258)

* ServiceAccounts: modernize SA creation interface

* ServiceAccounts: improve service account ID generation

* ServiceAccounts: remove unused method

* ServiceAccounts: Make SA ID display name dependent

* ServiceAccounts: Add tests for Service Account creation

* trim trailing whitespace

* Update pkg/services/serviceaccounts/api/api.go

Co-authored-by: Ieva <ieva.vasiljeva@grafana.com>

* Update pkg/services/serviceaccounts/api/api.go

Co-authored-by: Ieva <ieva.vasiljeva@grafana.com>

pkg/services/serviceaccounts/models.go

@@ -29,11 +29,6 @@ type UpdateServiceAccountForm struct {
 	IsDisabled *bool            `json:"isDisabled"`
 }
 
-type CreateServiceAccountForm struct {
-	OrgID int64  `json:"-"`
-	Name  string `json:"name" binding:"Required"`
-}
-
 type ServiceAccountDTO struct {
 	Id            int64           `json:"id" xorm:"user_id"`
 	Name          string          `json:"name" xorm:"name"`