User created databases and easy PR submission

[adamkucharski]

Suggestions by @smwindecker and @mgrabow2 highlighted two related features that could be helpful:

1. Would be useful to allow a user to create several local epidist objects (e.g. in a script) then store locally as a epidist_db object (e.g. in JS format), that can then be reloaded.
2. Would be nice for user to take their newly created epidist objects and easiy add to database. This might be easy-ish via PR if the above functionality stores locally in the same format (e.g. JSON).

[chartgerink]

Thanks to @joshwlambert for forwarding this issue in my direction.

In regards to adding objects to epiparameter, it could be possible to pre-fill an issue through the URL and open the browser so they only need to click "Open Issue". For example: Click here to open an issue with the text from this comment. This of course would then require the maintainer/someone to actually add the information (I do not recommend automating this).

For opening Pull Requests, it would require us to figure out how to do this in a usable manner. People using epiparameter cannot be expected to have the repository locally, so we would need to see whether we can create and commit the file without cloning the repo. This may be feasible if used the gh package directly. It would be more work to get this in a usable shape, but would provide a more direct path to contributing and crediting the contributors directly.

[joshwlambert]

Thanks for this @chartgerink, I think the use of automatically opening an issue would be useful for those that do not have the package cloned and are not familiar with opening pull requests. Something similar to functionality provided by usethis::use_release_issue().

It would also be useful to map the different types of package users and creating mechanisms for each to contribute. Perhaps there only needs to be two or three methods, a function that opens an issue being one of them. The other could be to use @adamkucharski's idea above to convert the <epiparameter> object to JSON (e.g. an as_json() function) that the user can call and then paste into the parameter library before making a PR.