[Keyboard] Added Cans12er keyboard (#7455)

* added cans12er keyboard

* updated readme

Updated the readme to conform with the provided template from the qmk_firmware githubpage

* Update keyboards/cans12er/README.md

Co-Authored-By: James Young <18669334+noroadsleft@users.noreply.github.com>

* Changed configuration

Changed the configuration based on the Change Request from PR #7455 made by github user noroadsleft

keyboards/handwired/cans12er/rules.mk

@@ -0,0 +1,32 @@
+# MCU name
+MCU = atmega32u4
+
+# Bootloader selection
+#   Teensy       halfkay
+#   Pro Micro    caterina
+#   Atmel DFU    atmel-dfu
+#   LUFA DFU     lufa-dfu
+#   QMK DFU      qmk-dfu
+#   ATmega32A    bootloadHID
+#   ATmega328P   USBasp
+BOOTLOADER = atmel-dfu
+
+# Build Options
+#   comment out to disable the options.
+#
+BOOTMAGIC_ENABLE = lite      # Virtual DIP switch configuration
+MOUSEKEY_ENABLE = yes       # Mouse keys
+EXTRAKEY_ENABLE = yes       # Audio control and System control
+CONSOLE_ENABLE = no         # Console for debug
+COMMAND_ENABLE = no         # Commands for debug and configuration
+# Do not enable SLEEP_LED_ENABLE. it uses the same timer as BACKLIGHT_ENABLE
+SLEEP_LED_ENABLE = no       # Breathing sleep LED during USB suspend
+# if this doesn't work, see here: https://github.com/tmk/tmk_keyboard/wiki/FAQ#nkro-doesnt-work
+NKRO_ENABLE = yes           # USB Nkey Rollover
+BACKLIGHT_ENABLE = no       # Enable keyboard backlight functionality
+RGBLIGHT_ENABLE = no        # Enable keyboard RGB underglow
+MIDI_ENABLE = no            # MIDI support
+BLUETOOTH_ENABLE = no       # Enable Bluetooth with the Adafruit EZ-Key HID
+AUDIO_ENABLE = no           # Audio output on port C6
+FAUXCLICKY_ENABLE = no      # Use buzzer to emulate clicky switches
+HD44780_ENABLE = no         # Enable support for HD44780 based LCDs