Support multiple shortnames in single template

[vlada-shubina]

Now the multiple short names are supported inside template group, but not in template scope. Consider supporting multiple short names inside template.

--list should also mention all possible short names for template group.

Related request: #2686

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update:

• several short names are already supported, we just don't support showing them.
• probably we should add ShortNameList property to ITemplateInfo instead of using separate interface for it IShortNameList