Remove $FreeBSD$: two-line nroff pattern

Remove /^\.\\"\n\.\\"\s*\$FreeBSD\$$\n/

Regularize the Netflix copyright

Use recent best practices for Copyright form at the top of
the license:
1. Remove all the All Rights Reserved clauses on our stuff. Where we
piggybacked others, use a separate line to make things clear.
2. Use "Netflix, Inc." everywhere.
3. Use a single line for the copyright for grep friendliness.
4. Use date ranges in all places for our stuff.

Approved by: Netflix Legal (who gave me the form), adrian@ (pmc files)

efivar(3): Fix some typos and improve style

- Fix some typos.
- Remove redundant semicolons from the synopsis section.
- Stylize variable names and types with Vt and Va respectively.
- Use a list to present non-implemented functions.
- Sort the order of the sections.
- Add a history section.
- Use Nm when "libefivar" is mentioned.

PR: 232626
Reported by: Tiwei Bie <btw@mail.ustc.edu.cn>
Reviewed by: bcr, imp
Approved by: krion (mentor, implicit), mat (mentor, implicit)
MFC after: 3 days
Differential Revision: https://reviews.freebsd.org/D17686

Add efidev(4)/efirt(9)

Document efidev(4), provider of userland access to EFI Runtime Services. A link is created to efirtc(4), which handles the time-of-day clock side.

efirt(9) is the kernel side of this.

Reviewed by: imp, kib (earlier version)
Differential Revision: https://reviews.freebsd.org/D16696

Create libefivar library. This library aims to provide
the same API as the GPL'd version of this library. It implements the common
Linux API for programatically manipulating UEFI environment varibales using
the UEFI Runtime Services the kernel provides. It replaces the old efi
library since it is programmed to a different interface, but retails the
CHAR16 to UTF-8 and vice versa conversion routines. The new name is to match
Linux program's expectations.

Differential Revision: https://reviews.freebsd.org/D8128
Reviewed by: kib@, wblock@, Ganael Laplanche