cleanup of config from scheduling package

[nirrozenbaum]

This PR continue the cleanup of legacy code.

• cleanup of scheduling config package. this was a global variable with env vars for scheduling, this should be removed.
• moved common/config/.. package to config/.... nothing is this package is common or should be common. it's the dedicated package for the config api (loading config from file/text).
• updated tests accordingly.

fix #1229

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[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: nirrozenbaum

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[ahg-g]

/lgtm