feat: implement ebreak

Breaks the processor, can
exit the testcase

feat: make RAM word aligned, add byte_enable

Support sb, sh, lb, lh using byte enable
instead of non-word aligned reads and writes.

test: add cpu testbenches for c programs

test: add ram test

chore: add makefile for both verilog and c

feat: implement sb, sh, lb, lh support via masking

test: add simple cpu test

test: add basic testbenches