Zsh ize

[Jefferson-Faseler]

Branch off of jordanwilson230#10
Couldn't target branch in @jordanwilson230's repo and didn't want to make @grzesuav the middleman.

Checklist

1. Addresses Issue: Make kubectl-prompt suitable for use with zsh jordanwilson230/kubectl-plugins#9
2. Instead of dependencies on the ~/.bash_profile throughout the code, the scripts can dynamically interpolate the shell profile. As of now support is Zsh and bash as the default.
3. Changes are GNU/BSD Compatible
4. Changes are applicable to the wider community.: I believe this is covered by the feature request.
5. Request help with testing if needed.
   I tested against prompt and it's family of sub-commands and flags, as well as image.