Add ability to set RequestOptions

[zack13532]

Adds a RequestOptions class and builder that allows users to set arbitrary request options int he client. These will be rejected by the server if the request option doesn't exist.

Example usage:

new GetFeaturesRequest(
            "testWorkspaceName", "testFSName", requestData, metadataOptions,
                new RequestOptions.Builder()
                    .option("latency_budget_ms", 5000)
                    .option("coerceNullCountsToZero", true)
                    .build())

ref RT-2159