[meta] Frontend decisions regarding styleguides and external libs

Groups all the open issues and MR with discussions about styleguides, linters and improvements.

JavaScript

Styleguide Documentation

• Decide on and document a convention for singletons !6620 (merged)
• List Vue conventions we should standardize on #23049 (closed)
• please upgrade jquery.timeago.js #21793 (closed)
• Use Rails-assets/Bower/NPM/Grunt/Gulp/BitLab to track and install frontend dependencies #14634 (closed)

Libs

• Decide what to do with task list lib. Open issues related to this lib: #22466 (closed) #22470 (closed) #3334 (closed) #2949 (closed) #21611 (moved) #18003 (moved) #21105 (closed)
• Why not upgrade to Lodash? #23110 (moved)
• Dropdowns #22223 (closed) #20754 (closed) #21552 (closed)
• Remove jQuery UI #18437 (closed)
• Remove jQuery Nicescroll #15664 (closed)
• Remove jquery-cookie !7085 (merged)
• Eliminate jQuery library use in favor of modern alternatives. #23022 (closed)

Sass

• Review scss-lint rules #23485 (moved)
• Add scss guidelines to development docs #22873 (moved)
• Unify scss-lint rules with www-gitlab-com #23318 (closed)
• Test Sass #23631 (moved)