vad : add initial Voice Activity Detection (VAD) support (#3065)

* vad : add initial Voice Activity Detection (VAD) support

This commit add support for Voice Activity Detection (VAD). When enabled
this feature will process the audio input and detect speech segments.
This information is then used to reduce the number of samples that need
to be processed by whisper_full.

Resolves: https://github.com/ggml-org/whisper.cpp/issues/3003

---------

Co-authored-by: Georgi Gerganov <ggerganov@gmail.com>

.github/workflows/build.yml

@@ -1253,3 +1253,23 @@ jobs:
           source venv/bin/activate
           pip install ane_transformers openai-whisper coremltools
           ./models/generate-coreml-model.sh ${{ env.MODEL_NAME }}
+
+  vad:
+    if: ${{ github.event_name == 'push' || github.event_name == 'pull_request' ||
+            github.event.inputs.run_type == 'full-ci' }}
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Build
+        shell: bash
+        run: |
+          cmake -B build
+          cmake --build build --config Release
+
+      - name: Test
+        shell: bash
+        run: |
+          ctest -R ^test-vad$ --test-dir build --output-on-failure -VV