🚧 [Pages] Create a redirect type of page

🚧 THIS ISSUE IS CURRENTLY A DRAFT 🚧

**Is your feature request related to a problem? Please describe.**

Some pages' URLs can change over time, and if the old link is still used somewhere, you need to keep two copies of that page.

**Describe the solution you'd like**

Create a new type of page that redirects the user to a URL.
The URL shouldn't be a Text input field but a component similar to the page selector from the header/footer settings to make things as clear as possible.

When the user clicks on `Add` to add a new page, there should be a dropdown to allow the user to select between `Page` and `Redirect`.

The only editable component should be the slug. The page title should not be editable, it should be `Redirect: [page to redirect to]`.

**Additional context**

A simple Text input URL field would be susceptible to issues over time if the domain or page URL changes.

The Header/Footer page input field is much more reliable in connecting internal & external pages.