Features proposition

[kennethrioja]

Summary of changes

• UI: The navbar is now sticked to the top of the window and minimizes when scrolling
• option: The main search box can be shown or not depending on value on tess.yml
• option: in the bottom of About/What is TeSS, it is possible to 'Learn more about TeSS' box, inspired by Taxilia : https://taxila.nl/about#link_tess

Motivation and context

• Those are changes I will implement for the CERN instance, I made them separated from other 'core' changes, these are mainly UI/options to enable for future TeSS instances.

Screenshots

N/A

Checklist

• I have read and followed the CONTRIBUTING guide.
• I confirm that I have the authority necessary to make this contribution on behalf of its copyright owner and agree
  to license it to the TeSS codebase under the
  BSD license.

[kennethrioja]

Respectively, see #1121 (UI sticky bar), #1123 (search box) and #1124 (acknowledgments)