Clean up unmarshal+marshall patterns in our code
Marshalling as a way to "verify" config is a bit messy, and it's particularly annoying when we have backwards-compatible parsing that we don't want to support marshalling for.
E.g., https://git.glasklar.is/system-transparency/core/stboot/-/blob/421899defff5dc695af82e11f59094a83fc096f9/host/config.go#L168-170 is needed because of things like https://git.glasklar.is/system-transparency/core/stboot/-/blob/421899defff5dc695af82e11f59094a83fc096f9/stboot.go#L231. IIRC I've seen similar unmarshal+marshal in other places, e.g., stmgr. So take a broader look on where this might be happening and why when resolving this one.
Edited by Rasmus Dahlberg