[IMP] Use radio widget in various views

+ some UI messages improvements

(Closes #1913)
[IMP] website.theme: add button in customize theme modal to show all theme modules
typo

s/nonexiting/non-existing
Merge pull request #1945 from MadeleineHero/master

[FIX] typo
[IMP] web_tip: convert web_tip model to v8 api
[FIX] web_tip: grant write permission to users
[IMP] web_tip: add support for list views
[ADD]product: add default product Miscellaneous