msiu's keymap for katana: standard QWERTY layout with planck like layers

This layout take a standard QWERTY default layer, with raise and lower layers similar to planck. It is for me to easily transition between keyboards. I put a few nav keys in the 'tree' middle, but I have come to realise I rarely use them as I am used to the planck layering. Top of the tree is a toggle for Dvorak layer.