[Alloy] Add CLI tools for inspecting and interacting with the Alloy API

[chrismytton]

Adds a couple of command line tools for inspecting designs in an Alloy instance, and interacting with the Alloy API via the methods in the AlloyV2 module.

• bin/alloy/inspect-designs - Lets you view one or all designs in a given Alloy instance and shows attributes, their types and whether they're required in a text format.
• bin/alloy/invoke - Allows you to call methods in the AlloyV2 module from the command line and pass parameters in via JSON. Inspired by the bin/fixmystreet.com/call-wasteworks-backend tool in FMS.

[chrismytton]

@MorayMySoc These might be useful for Bristol. Once you've got an API key you should be able to put it into a config file and then use the inspect-designs script to get details about the design, what the attributes are, attribute types and whether they're required or not.

And then when you're working on the integration the invoke script might come in handy when you need to see what the code is doing/seeing.

[MorayMySoc]

This works well for me - thank you!