Module efi

The boot loader for EFI executables

This will also handle devicetree installs and Shim authentication if either are available.

Safety

This uses unsafe in one place that is completely safe.

1. The set_load_options method requires unsafe to call, as it requires one condition that is upheld by the program. This one condition is that ptr must not be freed, or that it lasts long enough. This is ensured by the usage of a static RefCell, so this is safe.