Updates from EPTA version

[achalumeau]

This is an update from EPTA enterprise_extensions version. It is mostly to add new features and mainly compatible with previous version.

. blocks.py -> Change noise and common signal block to add new arguments, add features (e.g., fitting for Nbins) and re-order statements

. model_orfs.py -> Add diag argument to several orf functions, add new function

. model_utils.py -> Linting

. sampler.py -> Small change on 2 jump proposal functions

. chromatic/chromatic.py -> Allow a time window for the annual chromatic signal

. frequentist/optimal_statistic.py -> Simplify 2 if statements

[achalumeau]

@vhaasteren , Just a ping to mention that I just solved a conflict and linted the code. It should be good to merge.

[vhaasteren]

Sorry for being slow @achalumeau. In principle it's fine, except that the linting modified a lot of stuff that was already there. That means the code that was checked in was not properly linted before the github actions were this strict.

@AaronDJohnson, I think it's still fine to merge. What do you think?