Add UEFI installation instructions to partitioning page

[danboid]

The Haiku installer currently lacks support for auto creating a FAT32 UEFI boot partition so the user must manually create the EFI partition and then copy the contents of the EFI partition on the Haiku install disk into their target machines boot partition.

Until this procedure is automated by the installer it should be documented on this page:

​https://www.haiku-os.org/guides/installing/prep-partitions

[waddlesplash]

It is already documented on this page: ​https://www.haiku-os.org/guides/uefi_booting/

[danboid]

I didn't see that page. It might be an idea to add a link to it from the prep partitions page so others don't miss it?

Having read it now, I think the Basic Install section could be improved by adding something like.

"In most basic install cases it should be sufficient to simply copy (all of) the files from the Haiku install disks boot partition onto your machines EFI partition"