svd2workspace needed

[teburd]

Currently the svd2rust code generator generates an absolutely enormous 300kloc lib.rs for the imxrt series chips.

The teensy4rs authors manually split the generated code up into crates to solves this. There is an rfc to allow svd2rust to generate workspaces

rust-embedded/wg#338

This would solve the problem of very long compile times for the PAC crates that get generated here.

[teburd]

Looking into generated code similar to https://github.com/adamgreig/stm32ral and finding the results quite nice, as it only takes 2-3s to compile rather than 6min+