[Speech] Build our own PcmRecorder

[compulim]

Related to #3974.

Feature Request

In packages/bundle/src/speech/createMicrophoneAudioConfigAndAudioContext.ts, we are using PcmRecorder from Speech SDK:

• It is not using audio worklet via blob URL
• It is hardcoded to 16-bit mono 16 kHz, not dynamic according to the microphone input

[feature-request]