CL Interface Step 3: Create Cluster Cosmology Data Vector

[cavestruz]

We want to create a pipeline stage that gather the cluster number counts and cluster stacked profiles from precedent stages and output a unique SACC format that will be fed to FireCrown.

Question : What covariance do we need exactly and how will it be computed? => Probably just in TJPCov

• Save a SACC file with stacked profiles, counts and covariance and metadata (including cosmology)
• Test that we can ingest this in FireCrown.

(Initially written by Camille and edited by Marina)