Add new plot to rank script

Signed-off-by: Ruben Merz <ruben.merz@ieee.org>
Error checking for rs-snr script

Signed-off-by: Ruben Merz <ruben.merz@ieee.org>
Add experimental script to calculate and plot the correlation of the spectral efficiency with various metrics and factors

Signed-off-by: Ruben Merz <ruben.merz@ieee.org>