add: Added .notify and migrations, added levelup and protection events for notify, removed xpnotify completely

src/NadekoBot/data/strings/commands/commands.en-US.yml

@@ -4853,4 +4853,14 @@ minesweeper:
     - '15'
   params:
     - mines:
-        desc: "The number of mines to create."
+        desc: "The number of mines to create."
+notify:
+  desc: |-
+    Sends a message to the current channel once the specified event occurs.
+  ex:
+    - 'levelup Congratulations to user %user.name% for reaching level %event.level%'
+  params:
+    - event:
+        desc: "The event to notify on."
+    - message:
+        desc: "The message to send."