[RFE] Provide instructions on how to clean up the efi boot entries

[e-minguez]

There's sometimes where the efi boot manager contains multiple entries that are probably not needed anymore (especially for host being re-provisioned multiple times). It would be nice to document how to clean that list using efibootmgr or other methods (like on the uefi shell directly with bcfg as seen https://superuser.com/a/931016 )

Edit: Also seen this:

Be aware that in any of these cases, you may have leftover files on your EFI System Partition (ESP). You can delete them through normal file-manipulation commands, although depending on your OS, you may need to explicitly mount the ESP. If they aren't referenced, the files won't do any real harm, unless they consume so much space that they prevent you from installing another OS or updating your boot manager. The files will normally be stored in subdirectories of the EFI directory on the ESP; most OSes create subdirectories named after themselves or the companies that create them, such as EFI/ubuntu for Ubuntu or EFI/Microsoft for Windows.