Feature: Bool variable that will tell us if user has supported wallet installed

[Fica00]

Feature: It would be nice to have something like Web3.CanLogin() which will return true if user has a supported wallet installed and false if he doesn't for example I didn't have any wallet installed on my test phone and nothing was happening when I tried to connect, I had to open logcat and see what was the problem

If we had something like Web3.CanLogin() we cloud show a nice popup to user instead of wrapping the call in try catch to achieve same result