fix: Exception structure

[kenjis]

This PR changes the hierarchy of Exceptions for Shield as follows:

• BaseException
  • LogicException
    • InvalidArgumentException
  • RuntimeException
    • AuthenticationException
    • AuthorizationException

[MGatner]

Looks good! Your desired hierarchy would work if your PR to the framework for exception interfaces goes through. To that end we should consider making these exception classes @internal or final or both (which is probably a good idea anyway).

[kenjis]

Shield\Exceptions\HTTPException was not needed.
Since CodeIgniter\HTTPExceptionsExceptions\HTTPException was used in AuthenticationException,
I thought we needed an exception to wrap it. However, a closer look at the code showed that it only took the caught CodeIgniter\HTTPExceptions\HTTPException and converted it into a new exception.

So I removed Shield\Exceptions\HTTPException.

But I found AuthenticationException has some LogicException.
Since Config data may come from outside at runtime, these are considered RuntimeException.

[MGatner]

Just out of curiosity what is the advantage of implementing our own version if InvalidArgumentException? Logic errors by definition is code that needs fixing so shouldn't be caught, which makes me think that adding them to BaseException means someone might accidentally suppress a logic error by catching all BaseException.

[kenjis]

The reason for placing all exceptions under BaseException is to make it easier to know where the exception came from.

It is the developer's responsibility to decide how to handle the exception.

If a dev catches BaseException, it seems they want to catch all exceptions by Shield.