feat: resolve project-id and org-id using instance-id

[LucDeCaf]

Replaces #37 using a cleaner and (hopefully) simpler approach.

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Using a soon-to-be-introduced path in @powersync/management-client, automatically fetch the project_id and org_id flags when given the instance_id for a number of commands (where it makes sense to do so).

Example

Before:

powersync pull instance --project-id='project-123-456-789' --instance-id='instance-123-456-789'

After:

# Project ID is fetched from the management service if required
powersync pull instance --instance-id='instance-123-456-789'

NB: Test failures are expected until the next version of the @powersync/management-client releases.

[stevensJourney]

The logic here is becoming a bit more difficult to follow. Would it be possible to (pre)populate the orgId and projectId if only the instanceId is provided? Then, I would assume the logic of this function could remain as it was.

Otherwise, maybe lets add some code comments for the various paths.

[LucDeCaf]

The reason for the differing paths is because this function is sometimes called with an existing instance backing it and sometimes called when creating a new instance. I split the function into a separate one for each path, so that should make things clearer.