Tomographic real space measurement #215

Goal

Upgrade the existing measurement pipeline of real space statistics (2pcf, pure-E/B, COSEBIs) to tomography. Including the covariance measurement.

To do

• Write the loops to perform the iteration over redshift bins for the measurement.
• Implement the covariance. Maybe switch the real space covariance for the 2pcf from CosmoCov to OneCovariance to rely on a more documented software.