feat: impl MCDatabase for mariadb

db/db-sqlx-maria/src/get_all_unread_notifications.sql

@@ -0,0 +1,24 @@
+-- gets all unread notifications a user has
+SELECT 
+    mcaptcha_notifications.id,
+    mcaptcha_notifications.heading,
+    mcaptcha_notifications.message,
+    mcaptcha_notifications.received,
+    mcaptcha_users.name
+FROM
+    mcaptcha_notifications 
+INNER JOIN 
+    mcaptcha_users 
+ON 
+    mcaptcha_notifications.tx = mcaptcha_users.id
+WHERE 
+    mcaptcha_notifications.rx = (
+        SELECT 
+            id 
+        FROM 
+            mcaptcha_users
+        WHERE
+            name = ?
+        )
+AND 
+    mcaptcha_notifications.read_notification IS NULL;