Add support for NativeScript 8+

[serhiynovos]

Do you have any plans to add support for NativeScript 8 ? Currently I always have to go to node_nodules and change require("application") to require("@nativescript/core/application")

[hypery2k]

I tried it: https://github.com/hypery2k/nativescript-urlhandler/tree/feature/ns-upgrade

But actually I don't have much time for maintaining, so any PR to this branch is appreciated