Add convenience function for adding MAMP bin directories to path
Move mamp-related shortcuts to mamp file

* Only define them if MAMP is found on the machine
* Add function for reading the currently configured PHP version
Define php binary path for machines with MAMP
Remove EC2 config stuff on new MBP (for now)
Remove old unused shortcut
Add direnv hooks

Also set globsubst zsh option after most profile scripts,
as it causes obscure problems for things like the direnv hook