* daemon,tests: support forgetting device serial via API
this is done by posting {"action":"forget"} to /v2/model/serial
a flag no-registration-until-reboot is also supported
* many: more consistent naming Delete => DeleteByName on keypair mgrs
we actually want to introduce a Delete by key id on some of them now
* asserts: implement KeypairManager.Delete
* devicestate: Unregister deletes the device key pair as well
* tests: test device key deletion in generic-unregister
* asserts: avoid skipping the GPGKeypairManager.Delete test
pair --yes to --batch in the test
change the behavior of an alt attribute matcher when matching against
a list of values to match the alternatives to each element and not
overall
this is the approach used by all other matchers against a list of
values
the old behavior was unused and as the new tests show the new behavior
is quite productive. if really needed expressing for different
variants of a list can still be done by expressing variants for one
full level up
to avoid uses of this confusing old snapd make sure format: 5 is used
to mark snap-declarations that use alt attribute matchers going
forward
at least initially we don't support using snap commands to create/delete
keys under an external keypair manager, organize things such that though
we can produce appropriate error messages and we can implement
supporting this later if required
