[Keymap] Adds Egstad Preonic Profile (#6837)

* setup local build config, created npm build script to speed things up

* removed some profiles and gutted readme

* began configuring default and lower layout

* lower: fixed right arrow and added music toggle

* began configuring default and lower layout

* changed startup song

* updated comment typos

* I did that thing where i basically refactored everything :)

* Converted 2U key to 1U's

* Reorganized and tidied up

* Reorganized and tidied up

* space now changes layers

* updated numbpad

* updated readme

* removed unwanted files

* addressed change requests

keyboards/preonic/keymaps/egstad/readme.md

@@ -0,0 +1,11 @@
+# Egstad's Layout
+
+## Build
+
+- Cd into this directory, run `npm start`
+- Cd into root with `npm run qmk`, locate bin file "preonic_rev3_egstad.bin"
+- Drop that bin into QMK Toolbox and flash Keeb
+
+## Learnings
+
+ 1. Combos — Don't fuck with 'em. They made my keys feel sticky and increased typos. Would be great on macropad or something tho!