Integrate `Time_series-master` branch with main scripts/`basic plots`

[ppreshant]

Needs a lot of changes to account for general functions etc.
Best bet is to

• make a new branch from basic_plots, and
• bring over the features to read multiple sheets and join them from the Time_series-master branch
  Estimate: Will take 3 shifts of 1 hr each

Until then, use the specific branch that worked for the old datasets to get it to work

[ppreshant]

Added a multi sheet reading functionality in 8332b19, with enhancements in d3a8af8.

Now maybe merge the current branch to time series master to harmonize. Time series seems like a niche case and not worth integrating into the main script with an if() switch at this point like dose response was