Ceramic SDK can write data into ceramic-one after read

[nathanielc]

The SDK should provide an API to write an event to ceramic-one. The API should accept the JSON content of the document. It should then compute the diff and sign the event build the CAR file and submit the event to ceramic-one.

Implementation Notes

In order to do the diff the SDK will need to know the current state of the document. There are two ways know the state:

• Query the state via the ceramic-one API
• Cache the state from a previous write

We should prefer to cache the state over doing a read from the API for every write.

DOD

• Be able to write data to ceramic-one with a convenient API that abstract the details of constructing the event CAR data
• Code is browser compatible
• Minimize the amount of read call to the API that are needed

[stephhuynh18]

read api will be merged today (nov 13)

[mzkrasner]

Work to date is reflected in this branch: https://github.com/ceramicnetwork/ceramic-sdk/tree/mzk/stream-client

To-Do:

• Finish integration tests for stream-client (relies on /streams/ endpoint working - related to feat: add support for local file object store rust-ceramic#623)
• Finish integration tests for model-client (relies on /streams/ endpoint working - related to feat: add support for local file object store rust-ceramic#623)