GroovyScriptValidator does not have an XML element

[GlebDurygin]

Description of the bug or enhancement

In Jmix project, the legacy Validators implemented with Field.Validator have been moved to the compatibility module (#510). The GroovyScriptValidator is an analogue of legacy ScriptValidator, but this component does not have its own element in <validators/>. We should add <script/> element to the <validators/>:

• Inner script

  <validators>
  <script message="Validation failed">
      value ==~ /\d+/
  </script>
  </validators>

• "Class" attribute that defines path to the script

  <validators>
  <script path="path_to_the_script" message="Validation failed"/>
  </validators>