Reduce size of shinyApp for cran submission

[MaximMoinat]

Brought total file size down from 11mb to ~4mb, below the limit for cran submission.

Achieved by deleting reduntant third-party javascript, css and font libraries.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 86.72%. Comparing base (bc5a338) to head (b40aa7f).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #632   +/-   ##
=======================================
  Coverage   86.72%   86.72%           
=======================================
  Files          17       17           
  Lines        1085     1085           
=======================================
  Hits          941      941           
  Misses        144      144           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[katy-sadowski]

Thank you so much @MaximMoinat ! I tested it locally and the app is working fine, with no changes from usual. And R CMD Check passes with no notes now! I will get this released, and then proceed with the CRAN submission :)