Overhaul sly-stickers recording model

In preparation for more enhancements and a simpler UI.

* sly-stickers.el (sly-stickers-shortcut-mode-map): Use `sly-stickers-replay'
(sly-stickers--replay-map): Renamed from `sly-stickers--fetch-and-replay-map'
(sly-stickers--replay-help): Renamed from `slys-tickers--fetch-and-replay-help'
(sly-stickers--fetch-and-replay-1): Removed.
(sly-stickers--replay-state): New structure.
(sly-stickers--replay-prompt, sly-stickers--replay-read-binding)
(sly-stickers--replay-starting-state)
(sly-stickers--replay-next-state)
(sly-stickers--replay-valid-state-p)
(sly-stickers--replay-quit-state-p): New helper.
(sly-stickers-replay): Renamed and redesigned from `sly-stickers-fetch-and-replay'.