feat(settings): Add option to reset all stats

This commit introduces a feature allowing users to delete all their statistics from the app.

Changes include:
- A new "Reset data" dialog to confirm the action.
- A "Delete data ?" button in the settings screen to trigger the dialog.
- Backend logic to clear all statistics from the database.
- Fixes a crash on the stats screen when there is no data to display.
- Added new strings and translations for the reset data feature.

app/src/main/res/values-fr/strings.xml

@@ -86,4 +86,6 @@
     <string name="session_only_progress">Progression de la session uniquement</string>
     <string name="session_only_progress_desc">Montre uniquement la progression de la session actuelle, au lieu de la séquence entière.</string>
     <string name="media_volume_for_alarm_desc">Fonctionne uniquement avec un casque. Si le casque est déconnecté, l\'alarme retentit via le haut-parleur au volume des médias.</string>
+    <string name="reset_data">Réinitialiser les données</string>
+    <string name="reset_data_dialog_text">Êtes-vous sûr de vouloir réinitialiser toutes vos données ?</string>
 </resources>

app/src/main/res/values/strings.xml

@@ -113,4 +113,6 @@
     <string name="secure_aod_desc">Automatically lock your device after a timeout, while keeping the AOD visible</string>
     <string name="timer_reset_message">Timer reset</string>
     <string name="undo">Undo</string>
+    <string name="reset_data">Reset data</string>
+    <string name="reset_data_dialog_text">Are you sure you want to Reset all your data ?</string>
 </resources>