Installs the crap I like. Mainly ZSH and a GPG key.
If a GPG or SSH keypair has been added to the environment variables, they'll be automatically added to the environment.
Since SSH keys are now supported, I've added SSH key support to it.
Create the keys (pub and private), then store the base64 encoded string of public in SSHSIGN_PUB and the private key in SSHSIGN_PRV environmentals.
This is setup to detect a GPG directory stored as a base64-encoded string in a GNUGPG environmental. This can be created by running the following on a machine with the desired GPG key setup:
tar -czvf - ./.gnupg | base64 -w 0Inspired by this comment on a Gitpod issue regarding GPG signing.