add_linP_params module in notebooks

[armengau]

The module cup1d.planck.add_linP_params is not in this public version,

• it is asked in notebooks planck/plot[test]_planck_linP.ipynb, but not needed
• it is obviously needed for planck/add_linP_chains.ipynb

[andreufont]

Could you check out the new branch fix_add_linP? I forgot to update that module, since we only used it in old notebooks. https://github.com/igmhub/cup1d/tree/fix_add_linP

I checked that I was able to call that function, but not in the context of the notebooks (I don't have the original Planck chains anymore...)

[andreufont]

I also updated the notebook add_linP_chains, let me know if you can run it successfully and I will merge that branch and close the issue.

[armengau]

Yes, I checked the notebook add_linP_chains works now.

[andreufont]

solved in PR #28