Add STag detect

[MatjazBostic]

In the future, this repository will be included as a submodule in breadcrumb (and later also ezmap) instead of "breadcrumb_detect" subfolder. For this, STag detect functionality needs to be added to this repository.
I think that this is the repository that needs to be included here. Before including it here, it needs to be updated from the main stag_ros repository.