Implement new option for dotnet new --list: --source

[vlada-shubina]

Implement new option for dotnet new --list: --source
--source option additionally prints template source (package) and its name

See draft below:

Requirements:

• the following sources are supported: built-in, optional workload, package (user-installed) - corresponds to provider
• for built-in no source name is used
• for optional workload the name and version(?) of optional workload to be used
• for package the name and version (if available) to be used as name
• if template is included to several packages all of them should be printed
• if different language(s) are included to different package, they should be printed as a separate sub line