To minimize the number of arguments passed to `lzbt`, the loader config
is assembled outside `lzbt` and passed as a single argument.
Instead of reimplementing `consoleMode` under the `lanzaboote`
namespace, `config.loader.systemd-boot.consoleMode` is reused as is.
To access paths on the ESP before or after installing generations, split
EspPaths into general EspPaths that only depend on the path to the ESP
and EspGenerationPaths which additionally depend on generation specific
information (e.g. version number and initrd filename).
Raito Bezarius