Weighted convergence diagnostics

[n-kall]

Summary

Add weight support to ess_*, mcse_* and pareto_* diagnostics for rvars

Still some work to do to check validity of all functions, add tests, and cleanup, but progress is being made

Copyright and Licensing

By submitting this pull request, the copyright holder is agreeing to
license the submitted work under the following licenses:

• Code: BSD 3-clause (https://opensource.org/licenses/BSD-3-Clause)
• Documentation: CC-BY 4.0 (https://creativecommons.org/licenses/by/4.0/)

[mjskay]

Awesome, thanks for working on this! If this gets done before the rvar_weights branch is merged I'll merge it into that branch.

[n-kall]

I'll first make these functions assuming MCMC + weights, and then at a later time once the handling of MC draws is decided, they can be updated

[mjskay]

I'll first make these functions assuming MCMC + weights, and then at a later time once the handling of MC draws is decided, they can be updated

Sounds good to me. I think the attribute for that would best be done as another PR later.