Meta v1.2 Scope out needs to submit package to cran

[kaitejohnson]

Goal

Installing from CRAN is easier for a lot of users. We should scope out what we would need to do to get this package on cran.

Tasks

• [ ] separate github actions for R CMD check with and without --as-cran
• [ ] #188 (not yet!)
• [ ] write skip_on_cran() functions for any tests that use cmdstan, similar to in primarycensoreddist() https://github.com/epinowcast/primarycensoreddist/blob/d293504f4107af6f68654842b551b5b26856ce2d/tests/testthat/test-stan-primary_censored_ode.R#L1
• [ ] add examples to every function, or if an internal function than remove export and tag with @noRd
• [ ] make title capital letters

[dylanhmorris]

I am not convinced this should be a particularly high priority, particularly since we currently have a non-CRAN package (cmdstanr) as an essential dependency (see my comments in #188).