Add support for SMT & continuations for trace_decoder

[BGluth]

Tracking issue as this will take multiple PRs.

The goal here is to be able to build a single binary that can handle payloads consisting of any combination of MPT/SMT & txn/continuation atomic block units.

• Refactor trace_decoder to create overall structure with some logic stubbed out (Initial refactoring for SMT & Contination support in trace_decoder #197).
• Integrate Arpit's SMT decoding pre-image logic support (smt generation #127).
• Integrate Linda's continuation support ().
• Create logic to apply trace information for SMT w/ txns ().

[BGluth]

Closing as #275 supersedes this.