Removed unnecessary unsafe blocks and fixed a bug related to adding invalid sample values to `Utilized` random variables.

Minor changes to the README, changed dependencies to ODEM-rs crates in Cargo.toml to be able to develop them independently.

Profiled and improved performance of the event calendar. Made it private in order not to commit to early.

Reworked the `uom` integration: namespaces for all quantities and an extension trait for easier unit construction. Quantities are pushed into a separate macro for easier updating to later versions of `uom`.

Made the derive for `Config` rely on the definition of `DefaultConfig` in core, rather than just assuming its `(f64, (), ())`. This allows changing it later without having to touch the meta crate.

Cleaned up the root module of the library to prevent the IDE from suggesting private `use` directives in user projects.

Exporting the `uom` crate now, to allow the user to make themselves dependent on the version used here. Slightly tweaked the prelude.

Moved the benchmark results out of the target directory, since this one gets deleted on `cargo clean`.