[4.4] refactor: moving RedirectException.

[iRedds]

Description
Currently the RedirectException class is in the CodeIgniter\Router\Exceptions namespace.
I believe this exception is not related to routes but to the HTTP layer. Therefore, I propose to move it to the appropriate namespace.
The old class is marked as deprecated.

Checklist:

• Securely signed commits
• Component(s) with PHPDoc blocks, only if necessary or adds value
• Unit testing, with >80% coverage
• User guide updated
• Conforms to style guide

[kenjis]

If there is code that throws CodeIgniter\Router\Exceptions\RedirectException in apps,
it will break.

Why don't you catch the deprecated class in the framework code for backward compatibility?

[iRedds]

Nice catch. Thank you.

[kenjis]

LGTM!

[michalsn]

Nice.

[kenjis]

@iRedds Thank you!