The configuration used an invalid parameter name which caused the two
MaxScales to use the same directory for persisted configurations.
The test also tried to sync with the wrong server causing the same
listener to be created twice on the same port but on different MaxScales.
Cleaned up the startup and shutdown scripts to always start from a clean
state.
Moved and renamed the starting and stopping scripts from the REST API
tests to a common directory. This way the MaxCtrl tests can use the same
scripts to start and stop MaxScale.
Also moved the test configuration file into the `test/` directory and
changed some of the default directory locations.
