images: add 'manager' image

Replaces 6.x manager CI image with one in this repo to keep things consistent.

Also moves image definitions into a separate ci-image-defs.sh file for better editability.

added 1 commit

• cdd3d63f - images: add 'manager' image

Compare with previous version

requested review from @amrazek

mentioned in merge request knot-resolver!1554 (merged)

added 1 commit

• 960097f0 - images: add 'manager' image

Compare with previous version

added 2 commits

• 634b7551 - images: move bash scripts around
• 27932128 - README.md: fix outdated info

Compare with previous version

added 5 commits

• 27932128...50c3e700 - 2 commits from branch main
• 53d1612f - images: add 'manager' image
• e4f3b3d7 - images: move bash scripts around
• 77815b2a - README.md: fix outdated info

Compare with previous version

added 1 commit

• 802f9a25 - README.md: more information

Compare with previous version

mentioned in commit 95e3f925

merged