* remove non-functional gazebo headless arg
* remove unused namespace args
* simplify mavros launch, use mavros's px4.launch instead
* fix single_vehicle_spawn spelling
* formatting with xmllint: remove empty lines, set intent to 4 spaces, add xml tag for editors, add comments to break up spections
* remove old and deprecated launch files

- fixes #8858

So that they are unique.

- remove commas from a csv table file string to avoid import errors

includes range finder topic fix

We are running out of flash memory in px4fmu-v2 so removing all the
distance sensors from binary and adding then individually.
Right now only LeddarOne is not being buid.

More information: https://leddartech.com/modules/leddarone/

* add respawn_gazebo arg to be used with empty_world.launch
* catch rospy sleep method's exceptions
* fix copy-paste mistake in land state failure message