Solo1

Added
- `solo.hmac_secret.make_credential` method
- separate `solo key make-credential` CLI target

Changed
- remove credential generation from `solo.hmac_secret.simple_secret`
- demand `credential_id` in `solo key challenge-response`

Added
- challenge-response via `hmac-secret`

Changed
- implement passing PIN to `solo key verify`

Changed
- update fido2 to 0.7.0

Changed
- adjust to and pin fido2 0.6.0 dependency (conorpp)
- only warn if run as sudo

Added
- solo client improvements
- experimental interface to feed kernel entropy from key:
`sudo ALLOW_ROOT= /path/to/solo key rng feedkernel`