refactor(customize.html): out with the builder

[skip ci]
closes #1339

refactor(customize.html): features are lists with links

refactor(customize.html): use radio buttons for server selector

style(customize.html): ensure jquery checkbox looks consistent

refactor(customize.html): remove licensee email field

refactor(customize.html): form action is null and move jquery option below server

feat(customize.html/js): add js to generate s3 url

feat(customize.js): add hidden iframe to trigger file downloads