Update for a smoother experience

[coderste]

This could have a much better UX. For example we can use homebrew bundler to just pull in a Brewfile which would do all the app/tool installing we need.

We also don't need to install git ourselves like the repo says. We can just do all the homebrew installations first and then run git submodule update --init to pull in the git submodules we have for the iTerm plugin.

Also the iTerm preferences don't get exported and transferred properly.

We could maybe create a sort of tear down script which would copy all our preferences/aliases/config files from the current mac into this repo we then commit and then when we run the setup script on a new mac we know we have the latest changes rather than preference settings from 6 months ago which may be outdated (as was the case when I started a new job and realised I was missing some settings). The tear down script could also run brew uninstall against the same Brewfile to install all the custom applications we install for developing.