CONTRIBUTING: request only one submission type per change

We have some instances of contributors opening a GitHub pull request and
a Phabricator review for the same change, which divides or duplicates
review effort.

Reviewed by: markj
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D44856

CONTRIBUTING: mention sys/crypto as another "contrib" directory

Reviewed by: imp
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D44857

OpenSSL: Vendor import of OpenSSL 3.0.13

* Fixed PKCS12 Decoding crashes ([CVE-2024-0727])
* Fixed Excessive time spent checking invalid RSA public keys
([CVE-2023-6237])
* Fixed POLY1305 MAC implementation corrupting vector registers on
PowerPC CPUs which support PowerISA 2.07 ([CVE-2023-6129])
* Fix excessive time spent in DH check / generation with large Q
parameter value ([CVE-2023-5678])

Release notes can be found at
https://www.openssl.org/news/openssl-3.0-notes.html.

CONTRIBUTING.md: fix typo from commmit to commit

Signed-off-by: rilysh <nightquick@proton.me>
Pull-request: https://github.com/freebsd/freebsd-src/pull/960

CONTRIBUTING.md: Fix typos

Fix my own typoes.

Noticed by: kevans, cperciva

Sponsored by: Netflix

CONTRIBUTING.md: add note about upstreams.

Sponsored by: Netflix

CONTRIBUTING: class work

Add note about contacting me for professors including this as part of
their class work.

contributing: Add note about static analyzers

Please don't submit the raw results of some static analysis. Please do
submit the thoughtful results, though. Please test with kyua and create
test cases for any actual bugs that might be fixed.

CONTRIBUTING.md: add author identity info

We do not want @users.noreply.github.com addresses.

Reviewed by: imp
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D41918

CONTRIBUTING.md: reinsert double spaces

Reviewed by: imp
Pull Request: https://github.com/freebsd/freebsd-src/pull/788

CONTRIBUTING.md: minor changes

- Misspelled GitHub
- angle bracket not escaped correctly
- Double white spaces
- White spaces at EOL

Reviewed by: imp
Pull Request: https://github.com/freebsd/freebsd-src/pull/788

CONTRIBUTING.md: minor changes

Fix a singular/plural mistake, spelling error, a markup error, and a
handful of other minor changes.

Reviewed by: imp
Pull Request: https://github.com/freebsd/freebsd-src/pull/742

Import tcpdump 4.99.4

Reviewed by: emaste
Sponsored by: The FreeBSD Foundation

openssl: Vendor import of OpenSSL-3.0.8

Summary:

Release notes can be found at
https://www.openssl.org/news/openssl-3.0-notes.html .

Obtained from: https://www.openssl.org/source/openssl-3.0.8.tar.gz
Differential Revision: https://reviews.freebsd.org/D38835

Test Plan:
```
$ git status
On branch vendor/openssl-3.0
nothing to commit, working tree clean
$ (cd ..; fetch http://www.openssl.org/source/openssl-${OSSLVER}.tar.gz http://www.openssl.org/source/openssl-${OSSLVER}.tar.gz.asc)
openssl-3.0.8.tar.gz 14 MB 4507 kBps 04s
openssl-3.0.8.tar.gz.asc 833 B 10 MBps 00s
$ set | egrep '(XLIST|OSSLVER)='
OSSLVER=3.0.8
XLIST=FREEBSD-Xlist
$ gpg --list-keys
/home/ngie/.gnupg/pubring.kbx
-----------------------------
pub rsa4096 2014-10-04 [SC]
7953AC1FBC3DC8B3B292393ED5E9E43F7DF9EE8C
uid [ unknown] Richard Levitte <richard@levitte.org>
uid [ unknown] Richard Levitte <levitte@lp.se>
uid [ unknown] Richard Levitte <levitte@openssl.org>
sub rsa4096 2014-10-04 [E]

$ gpg --verify openssl-${OSSLVER}.tar.gz.asc openssl-${OSSLVER}.tar.gz
gpg: Signature made Tue Feb 7 05:43:55 2023 PST
gpg: using RSA key 7953AC1FBC3DC8B3B292393ED5E9E43F7DF9EE8C
gpg: Good signature from "Richard Levitte <richard@levitte.org>" [unknown]
gpg: aka "Richard Levitte <levitte@lp.se>" [unknown]
gpg: aka "Richard Levitte <levitte@openssl.org>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg: There is no indication that the signature belongs to the owner.
Primary key fingerprint: 7953 AC1F BC3D C8B3 B292 393E D5E9 E43F 7DF9 EE8C
$ (cd vendor.checkout/; git status; find . -type f -or -type l | cut -c 3- | sort > ../old)
On branch vendor/openssl-3.0
nothing to commit, working tree clean
$ tar -x -X $XLIST -f ../openssl-${OSSLVER}.tar.gz -C ..
$ rsync --exclude FREEBSD.* --delete -avzz ../openssl-${OSSLVER}/* .
$ cat .git
gitdir: /home/ngie/git/freebsd-src/.git/worktrees/vendor.checkout
$ diff -arq ../openssl-3.0.8 .
Only in .: .git
Only in .: FREEBSD-Xlist
Only in .: FREEBSD-upgrade
$ git status FREEBSD*
On branch vendor/openssl-3.0
nothing to commit, working tree clean
$
```

Reviewers: emaste, jkim

Subscribers: imp, andrew, dab

Differential Revision: https://reviews.freebsd.org/D38835

CONTRIBUTING: add intro describing the ways we accept contributions

Reviewed by: imp
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D39854

Vendor import of libcbor 0.10.2

Import libpcap 1.10.3

Reviewed by: emaste
Sponsored by: The FreeBSD Foundation

CONTRIBUTING.md: Fix checkstyle9.pl name

Pull request: https://github.com/freebsd/freebsd-src/pull/703

CONTRIBUTING.md: Suggest using checkstyle9.pl

CONTRIBUTING.md: correct developer certificate of origin link markup

Sponsored by: The FreeBSD Foundation

CONTRIBUTING.md: Suggest PR and Differential Revision lines

When there's an open PR and/or a Differential Revision, people
evaluating the pull request will want to look at them. Suggest that the
submitter include this information to make it easier to process.

Sponsored by: Netflix

CONTRIBUTING.md: Add in for github pull requests

Create a slightly longer version of the inforamtion available in the
handbook in the file that Github displays for more information about
contributing.

Sponsored by: Netflix