Disable owner priviledges upon foreclosure

[guidanoli]

📚 Context

For prior context on recoverable app funds, see #485.

After the application is foreclosed, the application owner can still change the application's outputs Merkle root validators, and therefore, steal user funds.

✔️ Solution

Make migrateToOutputsMerkleRootValidator revert if isForeclosed returns true.

📈 Subtasks

• Implementation
• Documentation
• Unit Tests