CLI output should be parse-able

As of today, the func cli is annoying to leverage in scripts or other tooling because we have to manually parse inconsistent formatting of the output. It would be great if it did something like the az cli, which defaults to JSON output (and lets the user specify other types of output).

Here's a few examples of the current format:
`func templates list`
```
C# Templates:
BlobTrigger
HttpTrigger
QueueTrigger
TimerTrigger

JavaScript Templates:
BlobTrigger
HttpTrigger
QueueTrigger
TimerTrigger
```

`func azure functionapp list`
```
Function Apps:
-> Name: example (westus2)
Git Url: https://user@example.scm.azurewebsites.net/
```

Start with the `func templates list` and `func azure functionapp list` commands shown in the issue, tracing where their current human-readable output is produced. Define the supported default and selectable output formats, then verify that both examples produce consistent machine-parseable output and that existing CLI behavior remains covered.

Written by the indexing model from the issue text.