Style docker files consistently

[ivanperez-keera]

I just noticed that docker files are not indented very consistently. For example, here the && start a column zero:

https://github.com/space-ros/docker/blob/76cd412a7379dd5a5ec338b7b75659afbbf0c9a1/space_robots/Dockerfile#L81-L83

but just a little bit later, they start at column 2:

https://github.com/space-ros/docker/blob/76cd412a7379dd5a5ec338b7b75659afbbf0c9a1/space_robots/Dockerfile#L87

I've always found that keeping a consistent style helps catch errors and propagate updates.

The following extra vertical space is not needed (and double space is not used elsewhere):

https://github.com/space-ros/docker/blob/76cd412a7379dd5a5ec338b7b75659afbbf0c9a1/space_robots/Dockerfile#L65

The following invocations of apt-get passes the argument -y last:

https://github.com/space-ros/docker/blob/76cd412a7379dd5a5ec338b7b75659afbbf0c9a1/space_robots/Dockerfile#L67
https://github.com/space-ros/docker/blob/76cd412a7379dd5a5ec338b7b75659afbbf0c9a1/space_robots/Dockerfile#L70

Others pass it first:

https://github.com/space-ros/docker/blob/76cd412a7379dd5a5ec338b7b75659afbbf0c9a1/space_robots/Dockerfile#L47

IMO the latter is preferable because it conveys the important information sooner and is less likely to be removed by mistake.