mitosis:datagrok: minor layout improvements (#2366)

mitosis:datagrok: minor layout improvements (#2366)

* mitosis/datagrok: make qwerty the default layout

* mitosis/datagrok: update readme to match qwerty default

* mitosis:datagrok: remove redundant name for transparent

meh, decided i don't need an extra key to represent "key that is
transparent because it's a modifier on a layer below." it's a maintenance
burden when moving other keys around

* mitosis:datagrok: add num lock on Blue + QWERTY T

* mitosis:datagrok: tap lshift = tab

we use tab completion a lot so let's get it onto an unmodified key somehow

* mitosis:datagrok: update readme

* mitosis:datagrok: improve notes in README

* mitosis:datagrok: note numlock in README