Add conversion to calculate the SNR in subdominant multipole moments
The purpose of this MR is to add the conversions to calculate the SNR in subdominant multipole moments introduced in https://arxiv.org/abs/2007.04313. In order to calculate the SNR in subdominant multipole moments the user simply has to provide --calculate_multipole_snr
to summarypages
. This MR updates and simplifies !514 (closed) to master.