Support ActionChain conversions

[nmaludy]

Currently only Mistral workflows are supported for conversion.

It should be easy enough to convert ActionChains as well.

We will need some flag on the CLI to say "this is a workflow of type X" so we know what converter to use. Alternatively, we could try to parse both Mistral and ActionChain and use whatever one validates properly.

[blag]

We will need some flag on the CLI to say "this is a workflow of type X" so we know what converter to use.

The pack converter script should be able to trust the action metadata, which identifies the type of workflow.

Alternatively, we could try to parse both Mistral and ActionChain and use whatever one validates properly.

This seems incredibly dirty, but I can't imagine AC workflows validating as Mistral workflows or vice versa, so this might work.

I think the converter script should have a flag to tell it which type of validator to use, and fall back to the implicit inference-via-successful-validation method if a flag isn't passed.