Continue the migration of mobile.startup to webpack.
= Acceptance criteria
[] Button built via webpack
[] Icon built via webpack
[] icons built via webpack
[] Panel built via webpack
[] Section built via webpack
[] Thumbnail built via webpack
[] Page built via webpack
[] After porting, update any global jQuery references to use the util.js module per our dev conversations
Note: Adding additional test coverage is out of scope and will be added separately.
Note: If tests cannot be ported (similar to View.js) due to reliance on sinon or jQuery leave them be. Only port the trivial tests.
= Sign off steps
[] Measure and record code coverage on [[ https://www.mediawiki.org/wiki/Reading/Web/Projects/Invest_in_the_MobileFrontend_%26_MinervaNeue_frontend_architecture/Progress?useskin=vector | the wiki page ]]