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This allows to do the same installation steps as for the singularity
image but locally with all packages as source packages.

- ar_track_alvar requires an older version of pcl.
- Use an alternative version of occupancy_grid_utils until upstream is
fixed.

Improve it in the meantime. The current issue is during the compilation
of ar_track_alvar because of changes in the pcl library (Melodic/Ubuntu
18.04 has 1.8 and Noetic/Ubuntu 20.04 has 1.10).

stdr_gui requires qt4 unavailable on Ubuntu 20.04.

The default apt-get command is interactive for this package.

Gaël wishes he could test before pushing.

RealSense cameras are not supported as of 2020-10-07.

- Use multiple rosinstall files
- Remove tab in robolab.rosinstall.
- Temporarily remove robolab_turtlebot because of package name conflict
with the official `turtlebot` package.
- Remove duplicates from robolab_melodic.rosinstall.

Add occupancy_grid_utils ROS package from source.