Speed up Ubuntu install ~3x: explicit packages instead of lamp-server^

[jsokol]

Summary

lamp-server^ is a tasksel "task" metapackage: it depends on the same apache2/mysql-server packages the Debian branch of setup_ubuntu_debian() already installs explicitly, but also pulls in a broad set of packages beyond the actual LAMP stack (CGI/Perl libraries, etc.) that SimpleRisk has no use for — confirmed by inspecting an installed image: 211 packages including libcgi-fast-perl, libcgi-pm-perl, libhtml-template-perl, Python stdlib bits, etc. It also meant installing whatever PHP version Ubuntu's own archive defaults to for that release, then immediately overriding it with the pinned Sury version and swapping Apache's active PHP module (from #40's PHP-version-pinning fix) — extra work for a result the explicit-install path gets directly.

Now that Ubuntu already gets the same Sury PHP8 repo Debian uses, Ubuntu can just take the same explicit apache2/mysql-server/phpX.Y install path Debian already proves works, with no lamp-server^ special-casing and no module-swapping dance needed. Test Dockerfiles updated to pre-install the same explicit packages instead of lamp-server^, for the same reason (and because lamp-server^'s pre-bake was most of the Docker build-step time in CI).

Test plan

• bash -n simplerisk-setup.sh — syntax check passes
• Full local Docker run (install → verify → uninstall → verify) on all three supported Ubuntu versions:
  • 22.04: 28/28 install checks, 13/13 uninstall checks, PHP 8.5.10 active.
  • 24.04: 28/28, 13/13, PHP 8.5.10.
  • 26.04: 28/28, 13/13, PHP 8.5.10, confirmed no courier-mta regression from the earlier sensible-mda uninstall fix.
• Measured timing improvement per OS, roughly 3x faster overall:

  	Before	After
  Docker image build	~9 min (22.04)	~27 sec
  Script install step	~14 min	~6.5–7 min
  Total per OS	~20–24 min	~7–8 min