Allow a directory to be passed as a preset, in which case all files
inside the directory (recursively) are treated as presets, loaded in
lexicographical order.
This allows one to compose a system by mixing in different presets, and
easily change their order of execution.
Status: WIP
Completed:
* Fixed flagged clippy lints
* Moved qemu(), main.rs::mount() and chroot() to the tools module.
* Moved constants in main.rs to constants.rs (including base packages
array)
* Renamed Presets struct to PresetsCollection to avoid confusion with
Preset struct
* Moved main() to the top of main.rs to highlight general logic path
* Added comments and docstrings to some functions
* Removed some uses of `use foo::*` to make the source of imported functions
and structs clearer
TODO:
* Move remaining code in main.rs to modules (except main())
* Break up create() function in to separate steps
* Log every command run (with arguments) to debug! when verbose flag is used
* Add docstrings for remaining functions and document constants (e.g.
why noatime is used)
* Remove remaining uses of `use foo::*`
* Consider renaming/moving tools module to address tool:: vs. Tool::
confusion
