4.5.0: SubMenus for GTEST

Goal:

Add submenus for gtest related tests in ut-core

What's Changed

• PR: gh #157 : Add changes for running individual tests on gtest submenu by @kanjoe24 in #166

Acceptance criteria:

The menu system should be in par with CUNIT counter part of ut-core

Uplink Info : RDK-55629

Full Changelog: 4.4.0...4.5.0