Migrate Floodgate players at join time to v2 database

Author: Smart123s

core/src/main/java/com/github/games647/fastlogin/core/shared/FloodgateManagement.java

@@ -86,9 +86,15 @@ public void run() {
                 profile.setFloodgate(true);
             }
         } else if (!profile.isFloodgate() && !isLinked) {
-            core.getPlugin().getLog().warn("Player {} is already stored by FastLogin as a Java Edition player.",
-                    username);
-            return;
+            if (profile.getDbVersion() == 1) {
+                profile.setFloodgate(true);
+                core.getPlugin().getLog().info(
+                        "Player {} has been migrated to the v2 database schema as a Floodgate user.", username);
+            } else {
+                core.getPlugin().getLog().warn("Player {} is already stored by FastLogin as a Java Edition player.",
+                        username);
+                return;
+            }
         } else if (profile.isFloodgate() && isLinked) {
             core.getPlugin().getLog()
                     .warn("Player {} is already stored by FastLogin as a non-linked Bedrock Edition player.", username);