Leap 15.3 respin setup

[nilxam]

https://build.opensuse.org/project/show/openSUSE:Leap:15.3:Update:Respin

• [x] Create openSUSE:Leap:15.X:Update:Respin and openSUSE:Leap:15.X:Update:Respin:ToTest
• [x] Create snapshot of standard repo eg. standard-leap-15.3 on openSUSE:Leap:15.3:Update, openSUSE:Leap:15.3:NonFree:Update and openSUSE:Backports:SLE-15-SP3:Update
• [x] Make sure disk limit rule is tweaked for product build images/local
• [x] Copy project attributes from openSUSE:Leap:15.3 if needed, OSRT:Config, OSRT:ProductVersion and OSRT:ToTestManagerConfig, you might need to adjust the value
• [x] Add needed product package and meta package
• [x] Fix skelcd-control-openSUSE - remember that workaround in the release package for additional update repos
• [x] Give the right permission on project/package for bots
• [x] Enable bots for openSUSE:Leap:15.3:Update:Respin - pkglistgen, project-installcheck, ttm, skippkg-finder
• [x] Tweak publish_opensuse.sh and provide a separate config for 15.3 Update:Respin (lubos)
• [x] Add config for Respin project to openqa-trigger-from-obs https://github.com/os-autoinst/openqa-trigger-from-obs
• [x] Add a new JobGroup on o3 for Respin testing, maybe "openSUSE Leap 15 Respin", we can reuse old "openSUSE Leap 15" jobgroup config (We can't re-use current group which is already used for 15.4)
• [x] Publishing script have to work for openSUSE:Leap:15.3:Update:Respin:ToTest -> ftp-stage. Who can do this?
• [x] Some changes to replace old Leap 15.3 content to the respined one on pontifex. Who should do this?

[nilxam]

Asked Andrii to take care of openqa-trigger-from-obs change

[nilxam]

we are at QU2 already