shiny app for diagnostics

[hillalex]

This PR adds a function biokinetics$inspect which opens a shiny app and allows the user to inspect data and priors before fitting. Will add the post-fitting diagnostic plots in a future PR.

It also adds a vignette detailing the input data plots available. Again, will add info about output plots in the next PR.

To test out the shiny app:

devtools::load_all()
data <- data.table::fread(system.file("delta_full.rds", package = "epikinetics"))
mod <- biokinetics$new(data = data, covariate_formula = ~0 + infection_history)
mod$inspect()

I haven't really attempted to write tests for the shiny logic. It's quite a simple app and the tests are a massive pain to write and run, so I don't think the time involved is worth it right now. So would be very useful if you could have a play around with it manually to confirm working as expected!

[codecov]

Codecov Report

Attention: Patch coverage is 10.89744% with 139 lines in your changes missing coverage. Please review.

Project coverage is 76.32%. Comparing base (45dab7e) to head (5d96c70).
Report is 10 commits behind head on main.

Files with missing lines	Patch %	Lines
R/inspect-model.R	0.00%	121 Missing ⚠️
R/shiny-utils.R	41.37%	17 Missing ⚠️
R/biokinetics.R	50.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##             main      #26       +/-   ##
===========================================
- Coverage   94.53%   76.32%   -18.21%     
===========================================
  Files           9       11        +2     
  Lines         567      718      +151     
===========================================
+ Hits          536      548       +12     
- Misses         31      170      +139     

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