Add --format to dotnet sln list

[jdraaijer-microsoft]

Add a --format option to dotnet sln list.

Closes #26303

Unresolved questions:

• What should I do with the untranslated translation entries?
• Is there a specific policy that says "don't have options with underscores", and if so, what should I replace console_with_header with, or are there better names for this?
• Is there a good way to indicate that console_with_header is the default value?
• Add tests that validate the output

[baronfel]

Left a single design note, but I'm very excited to see this! Thank you for taking the time to contribute this work.

[baronfel]

Out of curiosity, why use this encoder specifically?

[jdraaijer-microsoft]

I got confused and thought that this was what dotnet list package used, but seems I ended up using what dotnet tool list uses. I

s there a different one that is more common/would not pique your curiosity? :P

[baronfel]

I don't actually know what they use (the implementation is over in NuGet.Client repo I suppose, I could go look), but if you aligned with there decision I'm 100% ok with using that!

[baronfel]

What should I do with the untranslated translation entries?

Don't worry about these - there's an out-of-band process that ships the untranslated entries to our localization team, they make adjustments, and then they send those changes back to us in a PR.

[MiYanni]

A test should be added for this. Likely, one that runs the command with --format and then compares the output to see if it is correct.

[MiYanni]

Enum members should be PascalCase, so Text and Json.