webadmin: be more helpful when adding domains/accounts/addresses

by explaining (in the titles/hovers) what the concepts and requirements are, by
using selects/dropdowns or datalist suggestions where we have a known list, by
automatically suggesting a good account name, and putting the input fields in a
more sensible order.

based on issue #132 by ally9335

lib.ts

@@ -214,6 +214,7 @@ const attr = {
 	action: (s: string) => _attr('action', s),
 	method: (s: string) => _attr('method', s),
 	autocomplete: (s: string) => _attr('autocomplete', s),
+	list: (s: string) => _attr('list', s),
 }
 const style = (x: {[k: string]: string | number}) => { return {_styles: x}}
 const prop = (x: {[k: string]: any}) => { return {_props: x}}