[Keyboard] Add support for THE50 (#4844)

* Add support for THE50

A 50% custom keyboard designed and produced by LazyDesigners

* THE50 code-improvement

Implement the changes suggested by noroadsleft.

keyboards/lazydesigners/the50/the50.c

@@ -0,0 +1,9 @@
+#include "the50.h"
+
+void the50_led_on() {
+  DDRB |= (1 << 7); PORTB &= ~(1 << 7);
+}
+
+void the50_led_off() {
+  DDRB &= ~(1 << 7); PORTB &= ~(1 << 7);
+}