refactor(playout): add typings and fix linting errors

move EVENT_KEY_FORMAT to events module
properly type fetch queue
event start/end can be str or datetime

playout/tests/player/liquidsoap_gateway_test.py

@@ -0,0 +1,33 @@
+from libretime_playout.player.events import EventKind, FileEvent
+from libretime_playout.player.liquidsoap_gateway import create_liquidsoap_annotation
+
+
+def test_create_liquidsoap_annotation():
+    file_event: FileEvent = {
+        "type": EventKind.FILE,
+        "row_id": 1,
+        "start": "2022-09-05-11-00-00",
+        "end": "2022-09-05-11-05-02",
+        "uri": None,
+        "id": 2,
+        "show_name": "Show 1",
+        "fade_in": 500.0,
+        "fade_out": 500.0,
+        "cue_in": 13.7008,
+        "cue_out": 315.845,
+        "metadata": {
+            "track_title": 'My Friend the "Forest"',
+            "artist_name": "Nils Frahm",
+            "mime": "audio/flac",
+        },
+        "replay_gain": "11.46",
+        "filesize": 10000,
+        "dst": "fake/path.flac",
+    }
+
+    assert create_liquidsoap_annotation(file_event) == (
+        """annotate:media_id="2",liq_start_next="0",liq_fade_in="0.5","""
+        """liq_fade_out="0.5",liq_cue_in="13.7008",liq_cue_out="315.845","""
+        """schedule_table_id="1",replay_gain="11.46 dB",artist="Nils Frahm","""
+        """title="My Friend the \\"Forest\\"":fake/path.flac"""
+    )