Use Resource Manager (`/dev/tpmrrm0`) rather then `/dev/tpm0`

Hi,

The snapd reports the following error message when an application snap tries to open up the `/dev/tpm0`.
`stateengine.go:149: state ensure error: devicemgr: cannot connect to TPM: no TPM2 device is available`

Any application snap could block the use of `/dev/tpm0` and therefore, we might consider using the resource manager (`/dev/tpmrmx`) rather than using the `/dev/tpm0` as described here => https://github.com/snapcore/secboot/blob/master/internal/tcti/tcti.go#L29

In addition to that, potentially, we might want to change the snapd's tpm interface to block access to `/dev/tpmx` directly. => https://github.com/snapcore/snapd/blob/master/interfaces/builtin/tpm.go#L36

What do you think?

Thanks,
Bugra