Add getTemplatesCount methods to DDMTemplate API

• Type: Story
• Status: Closed
• Priority: Minor
• Resolution: Completed
• Affects Version/s: 6.2.0 CE M4
• Fix Version/s: 6.2.0 CE M4
• Component/s: Dynamic Data Mapping, Portal Services, Portal Services > Legacy
• Labels:
  • Qu
• Epic/Theme:
  • Quick_Win
• Git Pull Request: https://github.com/brianchandotcom/liferay-portal/pull/8427

This methods are needed by the resource importer and it's a simple and useful improvement