Make PaginatorInterface respond sooner, add yield-back values

Fix copy_context_with

Improve codebase coverage

Fixes regarding CI/CD and deployment

Documentation and help string changes

Add get/find helpers and JISHAKU_NO_UNDERSCORE envvar

Add `jsk curl`

Update to account for rewrite release

`jsk retain` now shows status if given no argument

Update `jsk [load|reload]` to use new Bot.reload_extension