remapping keys for `PgUp` and `PgDn`

[englut]

Hi there, I'm finding I'm having a hard time breaking my habits with vim for PgUp and PgDn. I use Ctrl-J and Ctrl-K, respectively. I was wondering if we can get two more options for remapping the keys of PgUp and PgDn. 🙏

Would be cool to be able to configure it like this:

[input.global-pgup]
special-keys=["PgUp"]

[input.global-pgdn]
special-keys=["PgDn"]