Adds Oh My Zsh setup

[hotmeteor]

Adds full Oh My Zsh setup if that's the shell the user selects.

1. Adds Zsh theme
2. Adds iTerm2 theme
3. Adds iTerm2 profile
4. Adds .zshrc config
5. Configures Python aliases
6. Installs Powerline
7. Configures iTerm2 by:
   • Downloading the iTerm2 python env and moving it to the right place
   • Install pip iterm2
   • Runs a script on iTerm2 start to set a dynamic profile as default

Other changes

• Installs Python as part of backend setup
• Installs Redis as part of backend setup

Based on @clair-rjacobsen notes here: https://app.getguru.com/card/c5R7dKki/Dev-Environment-Setup