[Keyboard] added custom keyboard (#6141)

* added keyboard_layout_jopr

* making it compile

* #pragma once instead of #ifndef and #define

* renamed and added keymap

renamed old "default" to "modded_white", added new "default" that resembles an ISO 105-key layout

* reordered keyboards/jopr/info.json to match order o layout array

* implemented most suggestions

* fixed missing ;

* fixed bootloader setting for rules.mk

* adopted standard layout matrix naming convention

* "fixed" commented-out code in keymaps

* changes to keymap layers and LEDs

Turns out adding a layer for ROYA-modified keycodes is more trouble than it's worth and works better by just defining a ROYA key.
Also, LEDs were set up incorrectly.
Lastly, implemented SysReq-Warning LED.

* moved forced NumLock code

just in case either it or the CapsLock & ScrlLock update code wouldn't both work otherwise

* rearranged media keycodes

* replaced Shifted keycodes with basic ones

* Apply suggestions from code review

Co-Authored-By: noroadsleft <18669334+noroadsleft@users.noreply.github.com>
* implemented suggestions by noroadsleft

* Apply suggestions from code review

Make ISO-Enter QMK Configurator-friendly

Co-Authored-By: noroadsleft <18669334+noroadsleft@users.noreply.github.com>
* Update readme.md

* Update keyboards/jopr/info.json

Co-Authored-By: noroadsleft <18669334+noroadsleft@users.noreply.github.com>
* moved keyboard to handwired folder

It was said that personal passion projects belong in there, even if they're not actually handwired

* Update readme.md