Bump deprecations

[teunbrand]

This PR does not fix an issue, but I see it as regular maintenance.

Briefly, it converts deprecate_warn0() to lifecycle::deprecate_stop() for functions/arguments that were deprecated prior to ggplot 3.3.0. It converts deprecate_soft0() to deprecate_warn0() for functions/arguments that were deprecated up to ggplot2 3.2.0 and removes examples.

I thought 5 years to be an OK horizon for deprecation warnings and I felt it was time to stop allowing things from the previous major version. Happy to make these timelines shorter though :)