Support Apache Pulsar protocol for SDK broker communiation

[marshallmcdonnell]

Create examples for pulsar here:

• https://github.com/INTERSECT-SDK/python-sdk/tree/main/examples

Then, this will pick up the end-2-end test of the example. Add pulsar run_example_test here:

• https://github.com/INTERSECT-SDK/python-sdk/blob/main/tests/e2e/test_examples.py#L31-L64

Then implement the broker client for pulsar here:

• https://github.com/INTERSECT-SDK/python-sdk/tree/main/src/intersect_sdk/_internal/control_plane/brokers

[Lance-Drane]

Regarding the binary encoding issue, Pulsar is one of the protocols which supports protocol-level headers, so support will be guaranteed to continue once we add it.

Until that issue is tackled, I wouldn't worry too much about the precise implementation details, as the BrokerClient interface is still too narrow (publish() only accepts a raw byte payload, the subscribe() callback functions will still only provide the raw byte payloads, etc.).

Once the general APIs have been defined for other protocols, I don't expect it would be difficult at all to refactor the Pulsar logic to send metadata in the headers.