New committer (ports): Älven (alven)

My first steps as a new committer, following the Committer's Guide: [0]

1. Add an Author Entity (doc/shared/authors.adoc)
2. Update the List of Developers and Contributors (doc/shared/contrib-committers.adoc)
3. Add a News Item (doc/website/data/en/news/news.toml)
4. Add a PGP Key (doc/documentation/static/pgpkeys/alven.key)

[0] https://docs.freebsd.org/en/articles/committers-guide/#conventions-committers

PR: 287620
Approved by: db@ (Mentor)