feature(sct.py): add `arch` option to list-ami-* commands
feature(sct.py): add `arch` option to list-ami-* commands

Now we can select the type of arch of AMIs we want to see:
```bash
hydra list-ami-versions -a arm64
hydra list-ami-branch -a arm64 master:all
```

scylladb/scylla-cluster-tests,scylladb/scylla-cluster-tests,scylladb/scylla-cluster-tests,scylladb/scylla-cluster-tests,scylladb/scylla-cluster-tests