mount_smbfs(8): Add the STANDARDS and HISTORY sections

mount_smbfs(8): Add the STANDARDS and HISTORY sections

- Document that mount_smbfs(8) only supports SMB1 and that SMB2 and SMB3
  are not supported at the moment. Suggest users to browse ports for
  software compatible with newer versions of the protocol.
- Copy supported servers list from README.
- Add a SEE ALSO section and reference the chapter about Samba in the
  FreeBSD Handbook.
- Add a HISTORY section.
- Style changes:
  - Use Dq instead of Em in the EXAMPLES section.
  - Mark command modifiers with Cm.

Reviewed by:	bcr
Approved by:	krion (mentor, implicit), mat (mentor, implicit)
MFC after:	1 week
Sponsored by:   Bally Wulff Games & Entertainment GmbH
Differential Revision:	https://reviews.freebsd.org/D17798