Display additional ad-hoc tables in the dashboard

[shankari]

from time to time, there may be additional ad-hoc tables that need to be displayed in the dashboard.

These are not critical to the core trip tracking functionality, but for additional services that might induce participants to install the app and provide data. They typically represent app state (e.g. the current ranking in the leaderboard; the current size of the bear). As such, they are not part of the core functionality, and we don't care too much about including them into a progressive system or making them be idempotent.

It seems like we should be able to easily create separate tables for them.

Since data:table automatically displays the retrieved data, we should be able to actually do this with very little code and in a generic fashion. For example, we could have an entry in the config that looks like this:

- supplementary tables
   - Checkinout
     tab name: "Bike Check in"

which could create a new tab called Bike Check in populated with data from the Checkinout collection.

we could even make the new table editable
https://www.r-bloggers.com/2018/11/editable-datatables-for-shiny-applications/

and allow people to specify the operations that they want to enable

- supplementary tables
   - Checkinout
     tab name: "Bike Check in"
     editable: D

Valid values for editable could be from CRUD (https://en.wikipedia.org/wiki/Create,_read,_update_and_delete) or at least CUD since R is the default

[shankari]

I'm adding comments to 4cbeb23
to think through how this might work and whether it is feasible

[shankari]

Note also that Shiny has built-in support for editable tables (https://blog.rstudio.com/2018/03/29/dt-0-4/)
but it looks like it only supports updates, not the full CUD. In particular, in the PR, there is a question around create and delete
rstudio/DT#480 (comment) which does not appear to be answered.

[shankari]

Another editable table module that might be more user friendly :)
https://github.com/jienagu/DT-Editor