MFC r271875, r272046, r272049, r272056
 -> Reference the test case "packs" to fix warnings
 -> Delete mentions to removed manpages
 -> Minor fixes to docs

Approved by: re (gjb)
MFC r271549 (nwhitehorn):

    Create /tmp/bsdinstall_etc even if we aren't starting the installer
    so that dhclient can write resolv.conf when used from the live
    environment.

PR:		176078
Approved by:	re
MFC 271745,271834,271899,271900,271913,272022,272023:

  Revert changes to shared code of the ixl and ixlv drivers to allow
  for easier long-term maintainability.

  Restrict the drivers to building on amd64 for now as it is
  only tested on that 64bit architecture.

  Just depend on PCI and neither INET nor INET6; also make sure we
  can build individual drivers and they do not depend on each other
  anymore.

  Reviewed by:	gnn, eric.joyner intel.com
PR:		193824
Approved by:	re (gjb)
MFC r271493,271688-271689,271696,271854,272139-272143:

Import HyperV Key-Value Pair (KVP) driver and daemon code by Microsoft,
many thanks for their continued support of FreeBSD.

While I'm there, also implement a new build knob, WITHOUT_HYPERV to
disable building and installing of the HyperV utilities when necessary.

The HyperV utilities are only built for i386 and amd64 targets.

Approved by:	re (gjb)
MFC the altera_atse.4.

This was intended to have been merged along with r256752.  This commit
contains the altera_atse.4 portions of r256752, r257656, and r270268.

Approved by:	re (gjb)
Sponsored by:	DARPA/AFRL
MFC r271526: MFV r271510:

Enforce 4K as smallest indirect block size (previously the smallest
indirect block size was 1K but that was never used).

This makes some space estimates more accurate and uses less memory
for some data structures.

Illumos issue:
    5141 zfs minimum indirect block size is 4K

Approved by:	re (gjb)