Unified "dash-name" convention for outputs in ci workflows.

There were errors with retieving constraints branch caused by
using different convention for output names (sometimes dash,
sometimes camelCase as suggested by most GitHub documents).

The "dash-name" looks much better and is far more readable so
we shoud unify all internal outputs to follow it.

During that rename some old, unused outputs were removed,
also it turned out that the new selective-check can
replace previous "dynamic outputs" written in Bash as well.

Additionally, the "defaults" are now retrieved via Python script, not
bash script which will make it much more readable - both build_images
and ci.yaml use it in the right place - before replacing
the scripts and dev with the version coming in from PR in case
of build_images.yaml.

(cherry picked from commit 017507be1e1dbf39abcc94a44fab8869037893ea)