Add input for past admission data

[thibautjombart]

We should provide a template and facilities for inputing data on past admissions. This would have to be optional, so the default behaviour remains the current inputs.

Items

• box tick input to uncover the file upload input, below the current data inputs
• reactive UI to show template download / file upload if the box above is ticked
• a template file, with 2 columns (date in format yyyy-mm-dd and n_admissions)
• a button for downloading template file (.xlsx)
• a button for uploading data
• an internal function in R/ to check / process uploaded data (with meaningfull errors where relevant)

Notes

There are ways to edit tables from shiny directly e.g.:
https://blog.rstudio.com/2018/03/29/dt-0-4/

But I think uploading xlsx is safer

[thibautjombart]

@samclifford tagging you here but feel free to un-assign; probably best done after the 1 tab reform (#42)

[samclifford]

I love the idea of a downloadable template. Suggest we also include a data dictionary as the second sheet if it's going to be an XLSX format.

For the error checking I'm thinking it might be worth running a date cleaner from https://github.com/reconhub/linelist rather than being sticklers for the date format. So long as it's unambiguous that's the main thing.

[thibautjombart]

I love the idea of a downloadable template. Suggest we also include a data dictionary as the second sheet if it's going to be an XLSX format.

For the error checking I'm thinking it might be worth running a date cleaner from https://github.com/reconhub/linelist rather than being sticklers for the date format. So long as it's unambiguous that's the main thing.

Yep, and yep, totally agreed :)

[thibautjombart]

Done as of ad1c056