Create common SSH key for Digital Ocean Droplet creations

[derickr]

Create a new SSH (public key) for shared use, to create droplets on Digital Ocean.

[svpernova09]

Created a new ed25519 key and saved public/private keys to $pbdemo-url/app/passwords/view/ba523185-c6cf-4e39-9539-8437f64a0c0f

[svpernova09]

As discussed in Slack, https://keepass.info/ for a password manager, we could put the SSH key and any other secrets in there, and then keep the DB file here in the repo.