Refactor process_submitted_jobs (#3666)

* Extract submitted-jobs context

* Extract submitted-jobs exit helpers

* Extract submitted-jobs preconditions

* Extract submitted-jobs assignment phase

* Extract submitted-jobs provisioning phase

* Rename submitted-jobs provisioning helpers

* Extract submitted-jobs finalization

* Clarify submitted-jobs provisioning outputs

* Extract submitted-jobs volume attachment

* Extract submitted-jobs instance materialization

* Extract submitted-jobs master fleet locking

* Inline submitted-jobs offer loop

* Reorder submitted-jobs helpers

* Simplify submitted-jobs termination helper

* Move submitted-jobs provisioning inputs to context

* Clean up submitted-jobs minor issues

Author: r4victor