Rename 'status' command to 'list' and introduce new 'status' which produces
more terse output more observable for both scripts and humans.

Also, it shifts hastctl closer to GEOM utilities with their list/status command
pairs.

Approved by:	pjd
MFC after:	4 weeks
Delete requests can be larger than MAXPHYS.
We don't need buffer to handle BIO_DELETE, so don't check buffer size for it.
This fixes handling BIO_DELETE larger than MAXPHYS.
Minor corrections.
Now that ioctl(2) is allowed in capability mode and we can limit ioctls for the
given descriptors, use Capsicum sandboxing for hastd in primary and secondary
modes. Allow for DIOCGDELETE and DIOCGFLUSH ioctls on provider descriptor and
for G_GATE_CMD_MODIFY, G_GATE_CMD_START, G_GATE_CMD_DONE and G_GATE_CMD_DESTROY
on GEOM Gate descriptor.

Sponsored by:	The FreeBSD Foundation
Accessing td_state requires thread lock to be held.

Submitted by:	Rudo Tomori
Reviewed by:	kib
When throttling a process to enforce RACCT limits, do not use neither
PBDRY (which simply doesn't make any sense) nor PCATCH (which could
be used by a malicious process to work around the PCPU limit).

Submitted by:	Rudo Tomori
Reviewed by:	kib