Updated user feedback & input controls

NOTE: This merge should be completed before the documentation merge in order to prioritize a functional version before the meeting on Monday.

Adds more user feedback (e.g., color cells where comment is needed, alert if year is outside analysis range, duplicated entries, etc.) and input controls (e.g., alert if provided site info does not match data, enforce proper data load order, indicate if output path has not been provided).

Functional conflicts with feature branch from Shanna should be resolved, but please pay extra attention for those popping up in your review. The ones I found mostly related to shiny alerts where the logic conflicted with the updates made to the "SavePSF" and "RunPeakFQ" handling.