[Keymap] Add issmirnov {user, ergodox, levinson} files. (#7239)

* Add issmirnov {user, ergodox, levinson} files.

There are enough interesting QMK tricks in these layouts that it seems
worth it to share with the broader community. Big thanks to Drashna for
inspiration, as well as all the wonderful creators of QMK documentation.

Some highlights:
- Common layout shared between levinson and ergodox_ez
- TAP_TOG macro for fast layer switching
- Autogenerated keymaps ascii art with git hooks

I will do my best to do periodic rolls here, but the source of truth
will always be https://github.com/issmirnov/qmk-keebs

* Incorporate review feedback.

- Remove CLEAR_EEPROM in favor of built in EEP_RST
- Remove custom handlers for audio on bootup and shutdown
- Remove plethora of unneeded includes
- Remove deprecated and dupliated config options

HUGE thanks to drashna for the review!

* Apply suggestions from code review

Huge thanks to drashna@ for a very thorough review and the very useful suggestions.

Co-Authored-By: Drashna Jaelre <drashna@live.com>

* Remove unclear optimization

This was an artifact from some other keymap I saw.

1 files changed, 49 insertions, 0 deletions

diff --git a/layouts/community/ergodox/issmirnov/README.md b/layouts/community/ergodox/issmirnov/README.md
new file mode 100644
index 0000000000..564edfe31d
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+# Ivan's Ergodox Config
+
+
+## Details about the layout
+
+- Shift and Cmd are One Shot Modifiers, so tapping them once will apply them to the next key. When tapped twice they will lock, until tapped again to clear.
+- When switching to other layers, any stuck modifiers are cleared in order to avoid unintended key combos
+- There are a few leader key combinations. Right now, `KC_LEAD` + `s` will open my wiki homepage.
+- All transparent keys have been replaced with noops to avoid layer bleeding.
+
+## Initial Setup
+
+### QMK
+
+```
+brew tap osx-cross/avr
+brew tap PX4/homebrew-px4
+brew update
+brew install avr-gcc
+brew install dfu-programmer
+brew install gcc-arm-none-eabi
+brew install avrdude
+
+git clone https://github.com/qmk/qmk_firmware.git
+git clone https://github.com/issmirnov/ergodox-layout.git \
+            layouts/community/ergodox/ismirnov
+```
+
+### Teensy utils
+
+Download and add both of these to $PATH
+
+- [hid_listen](https://www.pjrc.com/teensy/hid_listen.html)
+- [teensy loader cli](https://www.pjrc.com/teensy/loader_cli.html)
+
+## Flashing
+
+```
+make ergodox_ez:ismirnov
+teensy_loader_cli -mmcu=atmega32u4 -w -v ergodox_ez_ismirnov.hex
+
+# or just
+make ergodox_ez:ismirnov:flash
+```
+
+## Gotchas
+
+- If you get error: `dyld: Library not loaded: /usr/local/opt/isl/lib/libisl.15.dylib` then do `brew reinstall avr-gcc`
+- If `hid_listen` just prints out a ton of dots, update makefile with `CONSOLE_ENABLE = yes`