Command logic for credential management

[kaczmarczyck]

Together with #253 and #254, this PR implements the credential management command. Its logic is equivalent to #107, with the difference of only storing keys for credentials as state between calls to EnumerateCredentialsGetNextCredential.

• Tests pass

[kaczmarczyck]

For storage review ( @ia0 ) this should be very quick, only using all changes made in #254.

[ia0]

I reviewed Ctrl-F persistent_storage in all files.

I added a task that maybe iter_credentials usability could be improved. I wonder if I can remove the need to have iter_result (with compromise of each item being a Result).

[kaczmarczyck]

I think that would be easier indeed!

[kaczmarczyck]

The command is tested against Chrome. To test, change the default permission in pin_protocol_v1.rs to

self.permissions = 0x03 | PinPermission::CredentialManagement as u8;

[kaczmarczyck]

The 2 new commits don't show up in the conversation, since I merged after. The first is addressing the memory state issue. The other reworks the command state more to always reset timeout and state when either check fails. @jmichelp PTAL

[ia0]

I just checked occurrences of persistent_store.