* Path cleanup for SITL.

* Restructured sitl scripts dir.

* Set integration tests to use ekf2 for vtol.

* Fix sitl paths for mac.

This reverts commit 699b6a2c.

These will only start replay if there's an environment variable 'replay',
otherwise they do nothing.

We apply the parameters even before loading the modules, so that the
modules 'see' the same state as the recorded system had. We will have to
see how well this works in practice.

ROMFS: Clear out SITL mixers from deployed image, delete unused mixers, move test mixers to test config

Signed-off-by: Mark Charlebois <charlebm@gmail.com>