sys: Remove $FreeBSD$: two-line .h pattern

Remove /^\s*\*\n \*\s+\$FreeBSD\$$\n/

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.

Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix

Remove "All Rights Reserved" from FreeBSD Foundation sys/ copyrights

These ones were unambiguous cases where the Foundation was the only
listed copyright holder (in the associated license block).

Sponsored by: The FreeBSD Foundation

loader: remove BORDER_PIXELS

BORDER_PIXELS is left over from picking up the source from illumos
port. Since FreeBSD VT does not use border in terminal size
calculation, there is no reason why should loader use it.

MFC after: 1 week

loader: implement framebuffer console

Draw console on efi.
Add vbe framebuffer for BIOS loader (vbe off, vbe on, vbe list,
vbe set xxx).
autoload font (/boot/fonts) based on resolution and font size.
Add command loadfont (set font by file) and
variable screen.font (set font by size). Pass loaded font to kernel.

Export variables:
screen.height
screen.width
screen.depth

Add gfx primitives to draw the screen and put png image on the screen.
Rework menu draw to iterate list of consoles to enamble device specific
output.

Probably something else I forgot...

Relnotes: yes
Differential Revision: https://reviews.freebsd.org/D27420

Correct font.h comment describing vfnt font maps

Commit 41fb06651122 doubled the number of glyph maps in the vfnt format
from 2 to 4 to support double-width characters, but a comment describing
the maps was not updated to match.

MFC after: 1 week
Sponsored by: The FreeBSD Foundation

vt: if loader did pass the font via metadata, use it

The built in 8x16 font may be way too small with large framebuffer
resolutions, to improve readability, use loader provied font.

Move font related data structured to sys/font.c and update vtfontcvt

Prepare support to be able to handle font data in loader, consolidate
data structures to sys/font.h and update vtfontcvt.

vtfontcvt update is about to output set of glyphs in form of C source,
the implementation does allow to output compressed or uncompressed font
bitmaps.

Reviewed by: bcr
Differential Revision: https://reviews.freebsd.org/D24189