The creation and modification of moitor now supports the JSON API
conforming format generated by the GET endpoints.
Also added tests for creating and altering monitors via the REST API.
The tests now automatically start MaxScale before each test block and stop
it and perform cleanup after the test. This is done by simply calling the
`before.sh` and `after.sh` scripts before each test block.
The `test_rest_api` make target creates a discardable installation of
MaxScale which is used to launch a local instance of MaxScale. This local
instance is then used to test the REST API.
This is definitely not an efficient way to test the MaxScale but it allows
local testing without virtual machines or containers.
