feat(public execution): allow public execution to access commitment trees

[Maddiaa0]

Description

fixes: #784
provides infrastructure for #616

cannot stress how much of a draft this is

As part of the public -> private work, completion of l1 to l2 messaging consumption work, allow the public execution context to access the historic tree roots and implement acvm functions for them.

Checklist:

• I have reviewed my diff in github, line by line.
• Every change is related to the PR description.
• I have linked this pull request to the issue(s) that it resolves.
• There are no unexpected formatting changes, superfluous debug logs, or commented-out code.
• The branch has been merged or rebased against the head of its merge target.
• I'm happy for the PR to be merged at the reviewer's next convenience.

[Maddiaa0]

superceeded by #794, relevant commits cherry picked and out of scope items removed