MFC r258348:

  Document 'enabled' as boolean instead of string.

Approved by:	bapt (implicit)
Approved by:	re (gjb)
MFC r258347,r258349:

  Support SNI in libfetch

  SNI is Server Name Indentification which is a protocol for TLS that
  indicates the host that is being connected to at the start of the
  handshake. It allows to use Virtual Hosts on HTTPS.

PR:		kern/183583
Approved by:	bapt (implicit)
Approved by:	re (gjb)