add robot descriptions to sr-config

[kirstyellis]

to aid with issue#19

[guihomework]

@kirstyellis I have seen xacro files (not urdf files) have been added to sr-config now. This is rather strange.
I thought sr-config was meant to configure the hand per customer (settings, mappings, tuning, calib, OPTENV for muscle/motor tactile edc/can selection etc).

Indeed the urdf is usually also really tightly related to the customer hand. But the urdf.xacro where made generic (I did) to handle the customer settings actually. Xacro files are not per customer but rather generic I would say.

to get per customer files, to my opinion there should be a specific urdf file, with the correct pre-generated urdf into the sr_config, or at least a CMakeLists.txt xacro generation in sr_config with the correct args (depending on the customer) to create the pre-generated urdf into sr_config at compile time.

putting urdf.xacro out or sr_description is non-standard to me.

what do you think ?