Show result of address check to user

[fallerOfFalls]

When pasting an address in, many users stress about somehow missing a character or making a mistake in some other way, sending to some address that nobody owns. See this issue from official repo.

Could it show a reassuring "this is a valid address" statement (and perhaps even fetch basic info about it such as the current balance of that address, how many blocks) when a valid address is entered? Perhaps in green? And a red "this is not a valid address" otherwise. And maybe orange (or blue?) for "this is a valid address but has no open block on the network yet, is it a cold/offline wallet?"