New TurnKey GitLab version (18.1)

Changes:

• Update GitLab to latest GitLab-CE v17.3.0- via upstream apt repo.
• Confconsole: Bugfix, improve and update GitLab specific Let's Encrypt plugin - closes #1975.
• Inithooks: Improve and update GitLab inithook

Links

• Release meta-files (signature, manifest)