Implement GTest and change windows output path

Implement GTest as a testing infrastructure.
Make windows output binaries to the build folder instead of the release type folder (potentially issue further down the line)
Add a simple unit test for DestroyableComponent

CMakeVariables.txt

@@ -18,3 +18,5 @@ __dynamic=1
 # Set __compile_backtrace__ to 1 to compile the backtrace library instead of using system libraries.
 __maria_db_connector_compile_jobs__=1
 # Set to the number of jobs (make -j equivalent) to compile the mariadbconn files with.
+__enable_testing__=1
+# When set to 1 and uncommented, compiling and linking testing folders and libraries will be done.