Define View Navigation controls

[carter2422]

Per the design doc, the navigation keys should be as universal as possible across all editors. Additionally we should stop relying on the Numpad so much since many keyboards no longer include Numpads.

An argument can be made for using the Numpad for power users, since most professionals will opt for a more advanced keyboard, but these decisions should be left up to the artist. The goal of this keymap is to serve as a starting point for all new users. Since most keyboards do not include Numpads any longer I don't believe it should belong anywhere in the Simple keymap.