Add Dx_TimerInterrupt Library (#1746)

### Initial Release v1.0.0

1. Intial release to support Arduino **AVRDx-based boards (AVR128Dx, AVR64Dx, AVR32Dx, etc.) using DxCore**

Author: khoih-prog

repositories.txt

@@ -5133,3 +5133,4 @@ https://github.com/DIYODEmag/DIYsplay
 https://github.com/thomasfredericks/MicroOsc
 https://github.com/khoih-prog/ATmega_TimerInterrupt
 https://github.com/khoih-prog/ATmega_Slow_PWM
+https://github.com/khoih-prog/Dx_TimerInterrupt