Keyboard: DZ60 cleanup (#3994)

Keyboard: DZ60 cleanup (#3994)

* DZ60: Deleted K214 from LAYOUT_all

* DZ60: Delete matrix LAYOUT_2_shifts; replace with LAYOUT_all

After the deletion of K214 from LAYOUT_all, LAYOUT_all and LAYOUT_2_shifts are identical.

Deprecated LAYOUT_2_shifts in favor of LAYOUT_all.

* DZ60: refactor 256k_HHKB and itsaferbie keymaps to use LAYOUT_60_hhkb macro

Both keymaps previously used the LAYOUT_hhkb macro. After comparing the macros, the only difference between them was that LAYOUT_hhkb included the place of the ISO Backslash key. Neither keymap used this key, so both were refactored to use LAYOUT_60_hhkb instead.

LAYOUT_hhkb is now essentially unused by any keymaps in the repo. (More on that in a moment.)

* DZ60: bugfix for dbroqua keymap

This keymap had two layers that used the LAYOUT_true_hhkb macro and a third that used LAYOUT_hhkb. These macros have the same number of keys, but represent different physical layouts. As the "main" layers used LAYOUT_true_hhkb, switched the third layer to LAYOUT_true_hhkb as well.

The LAYOUT_hhkb macro is now unused by any DZ60 keymaps in the repo, and can be safely deleted.

* DZ60: bugfix for 60_ansi_arrow_fkeys, 60_plus_arrows, and stephengrier keymaps

All three keymaps had one layer in LAYOUT_all and one in LAYOUT_directional. Only difference between these macros is LAYOUT_all excludes the ISO Backslash position. As none of the keymaps used this position, all layers were switched to use LAYOUT_directional.

* DZ60: added layout mock-ups to dz60.h

Documenting the physical layouts that go with each matrix.

* DZ60: replace TMK SHIFT_ESC with QMK Grave Escape

Replaced all instances of keycodes that called TMK's ACTION_FUNCTION(SHIFT_ESC) with QMK's KC_GESC, and added config.h files so KC_GESC behaves as the deprecated TMK function did, except for the default keymap, which I thought should have the QMK standard behavior.

* DZ60: delete SHIFT_ESC code blocks

Deleted ACTION_FUNCTION(SHIFT_ESC) code blocks from keymaps that didn't use the functionality it provided.

* DZ60: deleted unused MODS_CTRL_MASk definitions

Was used in the now-deleted SHIFT_ESC code blocks. Interestingly named MODS_CTRL_MASK when it was actually checking the Shift keys. *shrug*

* DZ60: refactor jkbone keymap to use process_record_user

Replaced TMK action_function keycodes with QMK process_record_user equivalents.

* DZ60: delete unused layout macros

The macros LAYOUT_hhkb, LAYOUT_directional_625_space, and LAYOUT_60_ansi_split_bs_rshift_5x1u were unused by any keymaps in the repo, and have thus been deleted.

* DZ60: refactor iso_6u_space and iso_7u_space keymaps

Both keymaps refactored to use the LAYOUT_60_iso macro.

* DZ60: refactor dz60.h

Updated the notation of the switch arguments. Format is now:

`k<row><column>`

where `<row>` is `[0-4]` and `<column>` is `[0-9a-e]`.

* DZ60: refactor LAYOUT_60_iso_5x1u matrix

Updated matrix so `KC_ENT` belongs on the home row, which is consistent with LAYOUT_60_iso for the DZ60 as well as the ISO community layouts.

* DZ60: fix white space in dz60.h

I hate when indentation is inconsistent within a file.