run tests locally from CLion

[vol0n]

Description
Now all tests generated by utbot can be run on a server. It would be great for a user to be able to launch tests locally from ide,
in native environment. Also as CLion has its own CMake model and facilitates the UI for running tests, it would be great to use it as it is more comprehensive than current UI in plugin.

Expected behavior
When user generates tests, CMakeLists.txt is updated so that generated tests are recognized by CLion, and can be run by user.

Environment
Windows, linux, mac os + CLion Plugin + utbot server. This feature is only for CMake based projects.

Potential solution
Generated additional CMakeLists.txt in tests directory with instructions on how to build tests and include it from root CMakeLists.txt. Also ask user whether plugin should install GTest in case it is not installed

Context