Inconsistent access to Members/Member permissions

[gdude2002]

Having worked with a user on the KordEx server, I noticed the following:

1. InteractionCreateEvent doesn't seem to have a useful generic subtype for guild interactions, and also doesn't expose a nullable member property.
2. Member#getPermissions() ignores the permissions property, which refers to the permissions field present in the Member data provided by interaction events.

These two things together create a footgun which makes it difficult to generically check whether a Member has a given permission (or set of permissions). I'd like to suggest the following changes:

1. Create a GuildInteractionCreateEvent type inherited by the relevant interaction event subtypes, which exposes a member property encapsulating the data from the interaction event.
2. Update getPermissions() to return the permissions property by default, which - if provided - will contain all the member's applicable permissions.