Preonic Configurator update (#4598)

Preonic Configurator update (#4598)

* Preonic: refactor layout macros

Unify layout macro names across AVR and ARM.

- all layouts and matrices have moved/duplicated to their appropriate revisions
  - preonic.h now includes the appropriate header file from the selected revision
  - revision header files only contain layouts appropriate for that revision
    - Previously, all layouts were available in source for all revisions.
- removed KEYMAP layout macro alias (was unused)
- macros LAYOUT_preonic_1x2uC and LAYOUT_preonic_grid for AVR and ARM revisions
  - LAYOUT_preonic_grid has alias LAYOUT_ortho_5x12 for all revisions
- deleted LAYOUT_ortho_4x12 alias (not appropriate for this keyboard)
- ARM-based revisions have 1x2uR, 1x2uL and 2x2u matrices

* Preonic: updated revision headers to #pragma once

* Preonic: update Configurator files

Updated the Configurator files to reflect the previous changes in this branch.

- Preonic revs. 1 and 2 will use keyboards/preonic/info.json
- Preonic rev. 3 will use keyboards/preonic/rev3/info.json
  - This file will override keyboards/preonic/info.json when preonic/rev3 is selected in the Configurator.