Merge crucible-pcode

[langston-barrett]

Thomas Ulmer (@TCCQ) has been working on a frontend for Crucible that would ingest Ghidra's "low" pcode as part of an undergraduate thesis. The implementation so far is available here: https://github.com/TCCQ/crucible-pcode. This issue is a reminder for us to follow up and merge this work in a few months, when Thomas's thesis is complete.