Add websocket API based realtime ASR client (#143)

* Adding Realtime ASR Client

* Adding info in README

* Minor fix

* Minor fix

* Minor Fixes

* Refactoring

* chore: Adding Speaker Diarization Support

* chore: adding other fields

* chore: adding other fields

* chore: removed redundant methods

* adding completed event support

* chore: adding done event

* chore: adding 'is_last_final' bool handling

* chore: adding prompt arg

* chore: adding safe session update

* chore: adding the one-liner for realtime

* chore: adding python --custom-configuration

* chore: addressing comments

* chore: rename RealtimeASRClient to RealtimeClient