Port the pagination classes from bot and sir-lancebot

[shtlrs]

We currently have almost identical definitions of the LinePaginator class in both bot and sir-lancebot.

These classes can be ported over to bot-core and make them available for both of theses bots, and potentially any other one as part of the effort suggested in #85

Suggestion
@mbaruh has suggested to make use of views and buttons for the paginator and move away from reactions.

[shtlrs]

Done in #189