Automate init and add taulabs user

Fixes/Features
* Add dependency on bash to keep iproute2 happy
* Auto-installs wifi modules at boot (network interface still doesn't come up automatically)
* Creates a new taulabs user (passwd taulabs) and home directory (can now populate the home dir with whatever we want)
* Configures sudo for taulabs user
* Add udev rules to make spidev permissions allow read/write by taulabs user

Adding a non-root user that can do most things makes this a bit more safe from user errors.