#792 #814 Implement SQLite migration, allow last IP to be nullable in MySQL

- Old SQLite setups have the last IP column as NOT NULL but without a default value. With the new concept (where we don't set a last IP on player registration) it fails.
  - Create an /authme debug child that allows to migrate SQLite (tricky because SQLite does not support dropping or modifying columns)
  - Allow last IP column to be NOT NULL in MySQL as well (extend MySQL /authme debug child)
- Add TODO comments with follow-up issue to extend our commands with new registration IP field

src/main/resources/plugin.yml

@@ -173,6 +173,7 @@ permissions:
       authme.debug.group: true
       authme.debug.limbo: true
       authme.debug.mail: true
+      authme.debug.migratesqlite: true
       authme.debug.mysqldef: true
       authme.debug.perm: true
       authme.debug.spawn: true
@@ -196,6 +197,9 @@ permissions:
   authme.debug.mail:
     description: Permission to use the test email sender.
     default: op
+  authme.debug.migratesqlite:
+    description: Permission to perform a migration of SQLite.
+    default: op
   authme.debug.mysqldef:
     description: Permission to change nullable status of MySQL columns.
     default: op