TOOLS-3662: ship astools.conf via copy-if-absent install script

[a-spiker]

What

Standalone tool packages ship no astools.conf, so a fresh install leaves the user without the config template. This adds it back without re-introducing conffile-ownership conflicts with the aerospike-tools bundle.

• New pkg/astools.conf.sample: byte-identical copy of the canonical etc/astools.conf template.
• New pkg/postinst.sh (deb --after-install + --after-upgrade, rpm %post): seeds /etc/aerospike/astools.conf from /opt/aerospike/doc/aql/astools.conf.sample only when the file is absent.
• New pkg/mac-scripts/postinstall: same copy-if-absent logic for the macOS .pkg, target-volume aware.
• pkg/Makefile: stage the owned sample under /opt/aerospike/doc/aql/ (mac: /usr/local/aerospike/doc/aql/); wire the scripts.
• Removed the stale, unreferenced pkg/astools.conf.

The live /etc/aerospike/astools.conf is deliberately not owned by the package. Result: standalone tools and the aerospike-tools bundle coexist with no dpkg/rpm conflict over the path, and user edits are never touched.

Wired as both --after-install and --after-upgrade: fpm's deb template routes an install-only hook into after_upgrade() that never runs on upgrade or reinstall, so both are required for existing installs to get the file.

Tests

New .github/bin/test/test_astools_conf.bats runs in the linux and mac install jobs (kept out of the shared test_execute.bats, which is reused by the docker smoke job on the host):

• file created on install and matches the sample
• file recreated after removal + reinstall (guards the after-upgrade wiring)
• user edits survive reinstall

Docker smoke test asserts the image carries /etc/aerospike/astools.conf.

TOOLS-3662

[pvinh-spike]

LGTM