debian: remove pop-boot package

This package was briefly used when we transitioned to kernelstub, however
it should not be installed on modern systems as it can cause random loss of
boot options (which, in extreme circumstances, may cause the boot to fail).
We should thus remove this package from the build as every supported version
of Pop_OS uses kernelstub by default (on EFI systems; legacy boot systems are
a non-issue because they won't/can't be transitioned to kernelstub/systemd-boot)

Fixes #54 (by removing the offending file altogether)

debian/control

@@ -10,8 +10,3 @@ Architecture: all
 Depends: ${misc:Depends}, ${python3:Depends}, efibootmgr, python3-debian, util-linux
 Recommends: python3-systemd
 Description: Automatic kernel efistub manager for UEFI
-
-Package: pop-boot
-Architecture: all
-Depends: kernelstub, systemd
-Description: The fancy, magical, automatic boot package for Pop!_OS