refactor(core)!: move #[Priority] to tempest/support

[innocenzi]

This pull request moves Tempest\Core\Priority to tempest/support.

The reasoning is that it's a class used by multiple packages, which then depend on tempest/core and are harder to use standalone without Tempest.

This is a breaking change, as this attribute might be used in userland, so I added a rector rule for it.

[github-actions]

Benchmark Results

Comparison of refactor/priority against 3.x (9d11469f3c62f2922865eb2a80f7109cf15eee9a).

Open to see the benchmark results

No benchmark changes above ±5%.

_{Generated by phpbench against commit 5c88501}

[eshimischi]

This is a useful feature for developing libraries dependent on this framework. We ask you to consider adopting these changes soon.

[brendt]

I'm ok with this, but in order to do it non-breaking, did you consider using class_alias? We don't use it atm, but maybe it's not a bad idea?

[brendt]

Discussed the class_alias stuff on Discord. We'll not do it. Rather teach our community that we allow automated breaking changes in minor releases. I'll blog about it though and make the docs a bit more clear about it as well