adds settings that i forgot to add

src/video_subtitles/settings.py

@@ -0,0 +1,41 @@
+"""
+Reads and writes settings to a json file.
+"""
+
+import json
+import os
+
+HERE = os.path.dirname(os.path.abspath(__file__))
+
+SETTINGS_JSON = os.path.join(HERE, "settings.json")
+
+
+class Settings:
+    """Settings class."""
+
+    def __init__(self) -> None:
+        self.data: dict[str, str | int | dict] = {}
+        self.load()
+
+    def deepl_key(self) -> str | None:
+        """Return the DeepL API key."""
+        return self.data.get("deepl_key", None)  # type: ignore
+
+    def set_deepl_key(self, key: str) -> None:
+        """Set the DeepL API key."""
+        self.data["deepl_key"] = key
+
+    def save(self) -> None:
+        """Save the settings."""
+        # dump json to file
+        with open(SETTINGS_JSON, encoding="utf-8", mode="w") as f:
+            json.dump(self.data, f, indent=4)
+
+    def load(self) -> None:
+        """Load the settings."""
+        # load json from file
+        if not os.path.exists(SETTINGS_JSON):
+            self.data = {}
+            return
+        with open(SETTINGS_JSON, encoding="utf-8", mode="r") as f:
+            self.data = json.load(f)