Adding option to do flow matching based duration prediction

configs/experiment/ljspeech_stoc_dur.yaml

@@ -0,0 +1,16 @@
+# @package _global_
+
+# to execute this experiment run:
+# python train.py experiment=multispeaker
+
+defaults:
+  - override /data: ljspeech.yaml
+  - override /model/duration_predictor: flow_matching.yaml
+
+# all parameters below will be merged with parameters from default configurations set above
+# this allows you to overwrite only specified parameters
+
+tags: ["ljspeech"]
+
+
+run_name: ljspeech