[Task] patina_smbios: Add Rust constants for common SMBIOS header fields

[kat-perez]

It would be better to define these magic numbers with consts. Not sure if the const definitions are appropriate here or elsewhere, however. If elsewhere, I'm fine with this getting merged in and coming back after the fact to update.

Originally posted by @Javagedes in OpenDevicePartnership/patina-dxe-core-qemu#59 (comment)