- add new @hidden, @index, and @summary
  tag support to JavadocTagConstants, setting all for JDK 9
  except for @summary which is JDK 10
- in IModuleDescription add new methods to get the provides and
  uses service names and implement these new methods in
  DocCommentParser and AbstractModule
- in JavadocParser, add support @hidden, @index, and
  @summary
- add support for the new tags in TagElement
- modify JavadocCompletionParserTest

Change-Id: Icd266865ff6fd3fdd1056d567c0e91de613eb300
Signed-off-by: Jeff Johnston <jjohnstn@redhat.com>