modular_resources splitted. CONCERT data will go to concert_resources

[EdoardoRomiti]

To avoid issues such as the one in ADVRHumanoids/concert_description#12 we had to separate the CONCERT resources from the one in modular_hhcm.
Since modular_resources was contained as a submodule in both modular_hhcm and concert_description there would be two copies of the same repo in the same system, which can create conflicts.

This repo now only contains Pino-related stuff while for CONCERT you'll want to use https://github.com/ADVRHumanoids/concert_resources
I'll move all discussions related to the CONCERT modules to the new repo and please use that one from now on! @FraunhoferItalia @TUM-CPS-CONCERT