Access control: endpoint for searching single user permissions (#59669)

* initial commit

* clean up

* fix a bug and add tests

* more tests

* undo some unintended changes

* undo some unintended changes

* linting

* PR feedback - add user ID to search options

* simplify the query

* Apply suggestions from code review

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

* remove unneeded formatting changes

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

pkg/services/accesscontrol/accesscontrol.go

@@ -30,6 +30,8 @@ type Service interface {
 	SearchUsersPermissions(ctx context.Context, user *user.SignedInUser, orgID int64, options SearchOptions) (map[int64][]Permission, error)
 	// ClearUserPermissionCache removes the permission cache entry for the given user
 	ClearUserPermissionCache(user *user.SignedInUser)
+	// SearchUserPermissions returns single user's permissions filtered by an action prefix or an action
+	SearchUserPermissions(ctx context.Context, orgID int64, filterOptions SearchOptions) ([]Permission, error)
 	// DeleteUserPermissions removes all permissions user has in org and all permission to that user
 	// If orgID is set to 0 remove permissions from all orgs
 	DeleteUserPermissions(ctx context.Context, orgID, userID int64) error
@@ -53,6 +55,7 @@ type SearchOptions struct {
 	ActionPrefix string // Needed for the PoC v1, it's probably going to be removed.
 	Action       string
 	Scope        string
+	UserID       int64 // ID for the user for which to return information, if none is specified information is returned for all users.
 }
 
 type TeamPermissionsService interface {