Build correctly after D2535 merged into application code.

@DorianWinty That one could be a candidate to publish at rSCHEMA too.

Can't validate XML from unit test against it:

Looks good to me.

setup-nodesource-deb to upgrade first to test this as Node 6 (sic) doesn't provide a version for bullseye.

Solution implemented in D2525: we use /var/service.

Don't forget novolume

On Debian Bullseye, /etc/service is a symlink to /etc/runit/runsvdir/current.

Done. Last step is to ensure applications dependent of this image works correctly under Buster and Bullseye.

Partially reverted in rDPHPVIIFPMbbffa7c609bd.

Call runsvdir-init

Don't deprecate runsvdir-init, even if runsvdir-start isn't shipped by runit, we can maintain how we launch runit

Address runsvdir-init deprecation

As a workaround, I've compiled Git to 2.35.1 inside DevCentral container.

Builds fine:

Should be the final state before archiving the repository. It's possible to build image, and it uses the last PHP version, but we won't maintain that (e.g. no port to Debian recent releases).