[FEAT] Add in support for App Subscriptions

[AstreaTSS]

Problem Description

Quite a while ago, Discord added App Subscriptions, allowing apps to natively integrate with Discord to offer "premium" offerings through a subscription. Needless to say, interactions.py should add in the proper fields and classes to support this.

Proposed Solution

There are some major things to add:

• A PREMIUM_REQUIRED to application command responses.
• entitlements added to interaction context objects.
• ENTITLEMENT_CREATE and ENTITLEMENT_UPDATE events.
• A HTTP and bot method to list entitlements.

Alternatives Considered

No response

Additional Information

No response

Code of Conduct

• I agree to follow the contribution requirements.