RBAC: Add required component to perform access control checks for user api when running single tenant (#93104)

* Unexport store and create new constructor function

* Add ResourceAuthorizer and LegacyAccessClient

* Configure checks for user store

* List with checks if AccessClient is configured

* Allow system user service account to read all users

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

pkg/services/accesscontrol/actest/fake.go

@@ -75,6 +75,10 @@ func (f FakeAccessControl) Evaluate(ctx context.Context, user identity.Requester
 func (f FakeAccessControl) RegisterScopeAttributeResolver(prefix string, resolver accesscontrol.ScopeAttributeResolver) {
 }
 
+func (f FakeAccessControl) WithoutResolvers() accesscontrol.AccessControl {
+	return f
+}
+
 type FakeStore struct {
 	ExpectedUserPermissions       []accesscontrol.Permission
 	ExpectedBasicRolesPermissions []accesscontrol.Permission