Add ext.menus pagination module

[krittick]

Summary

Adds a pagination module, building on the initial work done by @LilJess13 and others in #68

Works with prefixed and slash commands, and can be sent as a response to an interaction.

Checklist

• If code changes were made then they have been tested.
  • I have updated the documentation to reflect the changes.
• If type: ignore comments were used, a comment is also left explaining why
• This PR fixes an issue.
• This PR adds something new (e.g. new method or parameters).
• This PR is a breaking change (e.g. methods or parameters removed/renamed)
• This PR is not a code change (e.g. documentation, README, typehinting, examples, ...)

[krittick]

Added two more key bits of functionality:

• self.message now stores the message that gets sent with the paginator
• on_timeout event added which disables all buttons associated with the paginator view (including custom view buttons) if disable_on_timeout is set to True (which is the default).
  • This results in a better user experience for views that time out instead of users receiving the "This interaction failed" error.

[VincentRPS]

looks good to me to be merged will have to test tho