Move custom errors from contracts to interfaces

[guidanoli]

📚 Context

Interfaces are essential for users to know:

• Which functions can be called
• Which events can be emitted
• Which custom errors can be raised

Without interfaces, users have to manually:

• encode function calls
• decode return values
• decode logs
• decode custom errors

In our codebase, however, there are several cases in which errors are defined in the contracts, and not on the interfaces. This means that users might not be able to decode these custom errors because they will be interacting with the contracts via their interfaces. The opposite doesn't happen, since contracts inherit these definitions from the interfaces. We must, therefore, make interfaces as complete as possible.

✔️ Solution

Move errors definitions from contracts to interfaces.