Factor out kernel ELF module into this repository

[hawkw]

This may require some work to decouple the ELF module from the rest of the kernel. Possibly blocked on establishing a common set of base HAL types.

[hawkw]

Started in 90c61e9. Currently there's a pretty heavy dependency on the kernel's memory crate. Need to figure out a reasonable way to handle this, I can think of a few options...