bintrans: Add base64 to name list in manual page.

MFC after: 1 week
Sponsored by: Klara, Inc.
Reviewed by: 0mp, pstef
Differential Revision: https://reviews.freebsd.org/D43558

usr.bin: Remove ancient SCCS tags.

Remove ancient SCCS tags from the tree, automated scripting, with two
minor fixup to keep things compiling. All the common forms in the tree
were removed with a perl script.

Sponsored by: Netflix

Remove $FreeBSD$: one-line nroff pattern

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

Add a quoted-printable encoder/decoder

As an example:
printf 'We don=27t know what to do with other=20worlds.=0D=0A' \
| bintrans qp -u

Differential Revision: https://reviews.freebsd.org/D34933

Reviewed by: debdrup (manpage)

Add the base64 command using b64encode and b64decode

Various scripts expect the base64 command to be present. We've had the
code and it's been exposed as b64encode/b64decode, but it wasn't widely
known under these names and the syntax is much different.

Reviewed by: delphij
Differential Revision: https://reviews.freebsd.org/D32945

b64encode: implement -w to wrap lines

This functionality is present in GNU base64 and I find it useful when
I want to generate random, ASCII-clean data of specific width.

Reviewed by: delphij
Differential Revision: https://reviews.freebsd.org/D32944

bintrans: move files to a new directory

And reflect the change in various places.