Keymap: A Planck style keymap with iris flair (#4677)

* A Planck style keymap with iris flair

 - Re-arrange layers to be more planck like.
 - move backspace to right thumb
 - replace backspace with minus, more useful for coding
 - replace center keys with brackets
 - MT(MOD_LCTRL and ESCAPE)
 - Use QMK-DFU for bootloader
   - add a soft reset to keymap

* Feedback from reviewers

 - remove redundant define (noroadsleft)
 - remove unused layer switch case (drashna)