Feat/add resize options

[kraigstrong]

Purpose

We wanted to add the -M flag to the mksysb call. Added a resize option that takes in a list of hashes containing both directory and size keys.

Example code:

resize:
    [
      {directory: /tmp, size: 5000M},
      {directory: /, size: 1000M}
    ]

Testing

Ran on AIX 7.1 and 7.2 successfully resized both /tmp and /

Notes

I had to remove the ssh_port feature due to not functioning on ruby 2.4. I added those commits back in manually, so you'll want to squash and merge rather than just merging my commits directly.