Backport few changes previously done in RHOAR container

[hhorak]

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Most notable changes:

• npx is used for nodemon execution
• GIT_COMMITTER_NAME and GIT_COMMITTER_EMAIL variables are set
• npm cache is cleared by rm -rf .npm (this is commented out, since we've actually had a test for specifically this, that cache is not removed)
• npm install is run once more when starting the node
• run npm run build when a build script is present
• run yarn if is set, although we do not ship yarn in our images

As a site-effect, these changes were done:

• Match also singular in the test_incremental_build
• Print the overall test result after the cleanup messages, so it is more visible.
• Use supported fedora 31 for v10 Fedora Dockerfile
• Move install-time steps to nodejs_container_install file (fixes also a wrong /usr/bin/nodemon symlink in case of SCLs)

More details in the commit messages in particular commits.

[hhorak]

[test-openshift]

[phracek]

Thanks for the PR! Nicely done with a couple of comments.

[phracek]

@hhorak Is this still valid? If so, I would prefer to update it. If not feel free to close it.