Feature/decrease needed memory (Issue 404)

[DavidPCoster]

As described in https://github.com/UCL-CCS/EasyVVUQ/issues/404, the PCE analysis code would sometimes use large amounts of memory. This pull request makes it possible to disable the calculation of the Correlation Matrices and Output Distributions. For one example, this decreased the memory usage to 2% of that previously required, and decreased the elapsed time to 12.7% of that previously required.

[djgroen]

I think this can be merged in, given that readthedocs is also broken in the main branch at the moment. We should try to fix that in the coming week imho.

[DavidPCoster]

Could someone with admin privileges on the repository look at why we are seeing

LGTM analysis: Python Expected — Waiting for status to be reported.                             Required
continuous-integration/travis-ci Expected — Waiting for status to be reported               Required 

with the status never being reported? I don't have sufficient access rights to do this myself!

@djgroen , @wedeling , ...

PS: readthedocs is no longer complaining after I committed a configuration file for it

[wedeling]

Could someone with admin privileges on the repository look at why we are seeing

LGTM analysis: Python Expected — Waiting for status to be reported.                             Required
continuous-integration/travis-ci Expected — Waiting for status to be reported               Required 

with the status never being reported? I don't have sufficient access rights to do this myself!

@djgroen , @wedeling , ...

PS: readthedocs is no longer complaining after I committed a configuration file for it

@DavidPCoster I gave you admin rights, you're basically one of the core maintainers at this point