deprecate_disable: add cask deprecate/disable reasons

[bevanjkay]

• Have you followed the guidelines in our Contributing document?
• Have you checked to ensure there aren't other open Pull Requests for the same change?
• Have you added an explanation of what your changes do and why you'd like us to include them?
• Have you written new tests for your changes? Here's an example.
• Have you successfully run brew style with your changes locally?
• Have you successfully run brew typecheck with your changes locally?
• Have you successfully run brew tests with your changes locally?

---

This PR adds some additional reasons for deprecate/disable in casks.

I would expect that discontinued would be used when a software is officially discontinued upstream, unmaintained used when a software has not received updates for a long time and may not work as expected on modern hardware, and no_longer_available when the software can longer be sourced from upstream.

It could be worth considering a no_longer_works style option, however this likely overlaps with unmaintained.

[p-linnane]

Makes sense. Thanks!

[MikeMcQuaid]

Thanks @bevanjkay!