create new tutorial on how to create the templates on learn.microsoft.com

[vlada-shubina]

Prerequisites:

• templates for template authors Create templates for template authors #2722
• validation tools: Authoring tools: templates & template packages validation #2623
• 1st version of authoring tools and/or tasks

The tutorial should include:

• creating the project template
  • adding the symbols
  • adding the post actions
• creating the item template
  • constraints, project context
• validation, packaging and publishing (via tools)
  • localization as the optional step: Add Documentation for Localization of templates  #2819