Add new `/batches/:batchId` endpoint

[slapec93]

Summary

There are 3 endpoints currently:

• GET /stamps - returns postage batches owned by the node with additional details only known by the owner node, such as utilization and label
• GET /stamps/:batchId - returns a single postage batch owned by the node with additional details...
• GET /batches - returns all globally available postage batches with limited information

There is no GET /batches/:batchId endpoint, which is bad for two reasons:

• No API symmetry
• When I only want to query a single postage batch not owned by my node, I first have to fetch all of them and then find from the collection. This can waste bandwidth and grow slower when the number of postage batches increase.

Motivation

I wanted to top up somebody else's postage batch, using a simple endpoint to first fetch the actual status of the postage batch

Implementation

Drawbacks

AI Disclosure

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