Consider changing `rcParams` default for `log_likelihood` to `False`

https://github.com/arviz-devs/arviz/blob/2d886383019eb95ea9174ea39070c15d03ffdb7e/arvizrc.template#L10

Paraphrasing from the PyMC issue: https://github.com/pymc-devs/pymc/issues/6266

> This evaluation can be quite expensive and require too much memory. I think it's safe to say most users don't make use of this information making it pretty wasteful.

Would require coordinating with other PPLs that use this variable to see if they agree and can help users make the transition.

CC @OriolAbril

Start with arvizrc.template at line 10 and read the linked PyMC issue to understand the cost and transition concerns. Confirm which other PPLs use this variable and whether they agree on a coordinated change; done means an agreed migration plan and an updated default.

Written by the indexing model from the issue text.