[refactor] refactor diff workflow

Diff should default to current working directory and comparison of HEAD and precious Verizon in the same repo

Diff -old version

We can then automatically copy for the user into tmp directory

• copy to .acmc/tmp/diff/version
• diff current head vs -old .acmc/tmp
• delete tmp

We can the suppot the same in a different working directory

Diff -d dir -old version

We can also suppot full config

Diff -d dir -v changed version -od dir -old old version