add private module to create model object for movement api

opendbm/api_lib/movement/_vocal_tremor.py

@@ -0,0 +1,18 @@
+from opendbm.api_lib.model import VideoModel
+from opendbm.dbm_lib.dbm_features.raw_features.movement.voice_tremor import run_vtremor
+
+
+class VocalTremor(VideoModel):
+    def __init__(self):
+        super().__init__()
+        self._params = [
+            "mov_freqtremfreq",
+            "mov_freqtremindex",
+            "mov_freqtrempindex",
+            "mov_amptremfreq",
+            "mov_amptremindex",
+            "mov_amptrempindex",
+        ]
+
+    def _fit_transform(self, path):
+        return run_vtremor(path, ".", self.r_config, save=False)