feat(engine): add new additionalResourceSuffixes to processes.xml

- the processes.xml property `additionalResourceSuffixes` can
  be used to specify additional suffixes during the scan for
  deployment resources

Example:

<process-archive>
  <process-engine>default</process-engine>

  <properties>
    <property name="isScanForProcessDefinitions">true</property>
    <property name="additionalResourceSuffixes">py,groovy</property>
  </properties>
</process-archive>

This scans for *py and *groovy files besides bpmn xml, cmmn and
diagram images.

related to #CAM-2383
feat(engine): deprecate process element in ProcessApplication.xsd

- process element is deprecate since 7.2.0
- use resource element instead

related to #CAM-2383