[v24.x backport] doc: promote Alpine Linux to tier 2 support - #66588

Backports #63737 to v24.x

kernel >= 6.12, musl >= 1.2.5 updated to align with lowest supported version Alpine Linux 3.21
see https://alpinelinux.org/releases/
see https://alpinelinux.org/posts/Alpine-3.21.0-released.html

Alpine 3.22 listed as example version

PR-URL: #63737
Reviewed-By: Matteo Collina [email protected]
Reviewed-By: Rafael Gonzaga [email protected]
Reviewed-By: Robert Nagy [email protected]
Reviewed-By: Chengzhong Wu [email protected]
Reviewed-By: Ruy Adorno [email protected]
Reviewed-By: Joyee Cheung [email protected]
Reviewed-By: Richard Lau [email protected]
Reviewed-By: Ulises Gascón [email protected]
Reviewed-By: James M Snell [email protected]
Reviewed-By: Mike McCready [email protected]

This manual backport is needed because bcf5850 from #63737 does not cleanly backport. The width of the table https://github.com/nodejs/node/blob/main/BUILDING.md#platform-list in the main and v24.x branches is different.

Background

Node.js does not support a platform version if a vendor has expired support for it.
The lowest Alpine Linux version supported is v3.21 according to https://alpinelinux.org/releases/, so
minimum versions are aligned to Alpine v3.21 and are bumped to:

kernel >= 6.12, musl >= 1.2.5

Documentation backport needed as reference for the support description in nodejs/docker-node for Alpine Linux x64 images. Docker documentation needs to move from describing these builds as "Experimental" to categorizing them as falling under "Tier 2" support - see musl builds for Alpine.