Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Merge r252230:

Implement ifconfig_wlanX="HOSTAP".

Not only this is a bit cleaner, it allows multiple instances of hostapd to be
running on the system host, useful for simultaneous dual-band WiFi.
This is similar to ifconfig_wlanX="WPA" but it uses /etc/hostapd-wlanX.conf.
Compatibility with hostapd_enable=YES/NO was kept.

MFC r230099:

Change rcvar= assignments to the literal values set_rcvar
would have returned. This will slightly reduce boot time,
and help in diff reduction to HEAD.

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

As previously discussed, add the svn:executable property to all scripts

rc support for vaps

Add reload functionality.

PR: conf/116659
Approved by: sam, erwin (mentor)

- Add a startup script for hostapd.
- Document associated variable in rc.conf(5).

Approved by: dougb
MFC after: 1 week