Include `stan_surv` in CRAN release of rstanarm?

Summary:

It would be amazing if we could finally merge the feature/survival branch into rstanarm, per this discussion on Apr 29. I'm surfacing this as a stand-alone issue to aid discussion around this.

I would hate to see this die on the vine, and not make it into wider use. What needs to happen to get this over the finish line?

Description:

The goals are (at a minimum):

1. Ease installation pain for users, particularly on Windows.
2. Access to rendered documentation & vignettes.
3. Regular (automatic) testing of stan_surv and related functions.
4. Maintenance of functionality, and adding new functionality.
   • I can contribute some time, but could use help.
   • @sambrilleman suggested recruiting a post-doc or researcher to help with maintenance.

Some options for release & installation:

• Merge feature/survival into master, release on CRAN (and elsewhere)
• and/or schedule updating the built binaries for feature/survival branch, hosted on mc-stan.org. [is this already being done?]
• and/or, add this branch to regular builds available through r-universe, which would also make the documentation available.

Reproducible Steps:

See related issues: #500 , #566 , etc.

RStanARM Version:

2.21.3

R Version:

N/A

Operating System:

N/A

Start by reviewing the feature/survival branch and related issues #500 and #566, then compare the proposed CRAN, mc-stan.org, and r-universe release paths. This is done when a release and maintenance plan is agreed, with stan_surv available through the selected channel, rendered documentation present, and regular testing established.