add management of SSH keys, allow selecting authorized keys on instance creation
We should have an easy way to track SSH keys per tenant and add them to new instances (specific keys selected at instance creation). These would have to be put in cloud-init vendor data, so some changes to rhyzome-openwrt would also be needed (rhyzome-openwrt#6)
- add database table to track SSH keys per user, including a name for each key
- add database table to track which SSH keys are assigned to which instance
- add API endpoints to add, list, delete and maybe rename SSH keys per user
- add API endpoint to list SSH keys per instance
- add optional SSH keys field to instance create request body
- add field for SSH keys to Instance REST response