consider changing data logic

atm. the app loads all the data stored in multiple files (cases, death, hospitalizations, per us/states) and then one of the first steps is to filter them again by targetVariable (cases, deaths, ...), scoreType, and location.

one option would be to load only the data that is really needed and better split the up in multiple files (targetVariable x score x location (nation or states)). This would reduce the initial loading time and with https://shiny.rstudio.com/reference/shiny/1.6.0/bindCache.html shiny could take care of caching datasets.

No files or tests are named. Start by tracing where the app loads the cases, deaths, and hospitalizations data for national and state locations, then follow the filtering by targetVariable, scoreType, and location. Done would mean agreeing on a data-loading and caching design that avoids loading unnecessary datasets and improves initial load time.

Written by the indexing model from the issue text.