chore(engine): move Spring dependency back to compile scope
chore(engine): move Spring dependency back to compile scope

- if in scope provided, all projects that use camunda.cfg.xml for testing
  would have to declare an explicit spring-beans dependency (even if they
  are otherwise non-Spring projects); that would affect a lot of our users

related to CAM-3359

ingorichtsmeier/camunda-bpm-platform,falko/camunda-bpm-platform,camunda/camunda-bpm-platform,ingorichtsmeier/camunda-bpm-platform,falko/camunda-bpm-platform,ingorichtsmeier/camunda-bpm-platform,langfr/camunda-bpm-platform,ingorichtsmeier/camunda-bpm-platform,langfr/camunda-bpm-platform,langfr/camunda-bpm-platform,falko/camunda-bpm-platform,camunda/camunda-bpm-platform,camunda/camunda-bpm-platform,camunda/camunda-bpm-platform,falko/camunda-bpm-platform,falko/camunda-bpm-platform,ingorichtsmeier/camunda-bpm-platform,langfr/camunda-bpm-platform,langfr/camunda-bpm-platform,ingorichtsmeier/camunda-bpm-platform,camunda/camunda-bpm-platform,falko/camunda-bpm-platform,langfr/camunda-bpm-platform,camunda/camunda-bpm-platform