Make ClientEvents, CollectorFilter and Message types generic.

[VimHax]

Please describe the changes this PR makes and why it should be merged:

I've added some generic type parameters for the following types for the respective reasons stated below.

-> CollectorFilter - I feel that this type would benefit from being able to define exactly what parameters will be passed in to the function. Not only does this leave less room for mistakes but it also makes it so users don't have to work with the type any as much when they're using TypeScript.
-> ClientEvents - This type has been given a generic parameter which dictates which events will emit partial data. This is useful as redundant checking for partial data won't be required if the user has not enabled the respective partial in the ClientOptions.
-> Message - The generic parameter for this type describes whether or not the message was sent in a guild. When you're working with messages you often have to check whether or not Message#guild is null even when you're pretty certain it isn't, inserting Message#guild as Guild everywhere is also much less elegant. This parameter can also be used to add more type information to the return types of some functions, such as Message#reply which will always return a Message which was sent in a guild if the original message was sent in a guild.

Status and versioning classification:

• Code changes have been tested against the Discord API, or there are no code changes
• I know how to update typings and have done so, or typings don't need updating

[iCrawl]

This needs a rebase.

[VimHax]

I merged the changes into master, will that do?

[VimHax]

Should've made separate PRs for each of the features I implemented.