Display log of JSON documents via the CLI

[callumforrester]

As a developer I would like to produce a set of copy/pasteable JSON documents in a log while I am running plans so that I can use them as test data for downstream applications.

Prior Art

Running blueapi controller listen will log all events coming off the message bus, including bluesky documents and other blueapi events. There is a WIP PR to provide filtering down to just documents: #337, which allows the user to write blueapi controller listen -t data.

However, that is not enough as the logs still aren't valid JSON, they are printouts of python dictionaries.

Possible Solution

Take over and complete #337, either include a format argument or raise in a separate PR such that a user can type blueapi controller listen -t data -o json and have the documents printed out in valid JSON form.

Acceptance Criteria

• blueapi controller listen -t data -o json (exactly syntax may vary) will print out valid JSON of all documents produced by blueapi until the user presses CTRL-C
• Tests in CLI tests

[callumforrester]

Done as part of #539