Collect Alpine Linux security advisories from https://security.alpinelinux.org/ #2158

Currently we import data from https://secdb.alpinelinux.org/, but we also have advisories at https://security.alpinelinux.org/.
For example https://security.alpinelinux.org/vuln/CVE-2025-15224 contains much more information than secdb, including fixed/affected versions summaries, references.