[WIP] Memoization tables

[imalsogreg]

Add memotables to the pact state. We will temporarily ignore exactly what this will eventually be used for.

For now, we only want a memo table to exist in the pact state, and we provide a repl-only function to add entries to the memo table. This command should put (shift 10 1) => 20 into the memo table:

pact> (env-memoize shift 10 1)
"Ok"

In subsequent evaluations that include (shift 10 1) as a subterm, 20 should be substituted immediately instead of recomputing (shift 10 1).

The PR does not work right now:

pact> (env-memoize shift 10 1)
...
<interactive>:1:0:Error: Expected def: native `shift`  ...

I'm still trying to fix this.

PR checklist:

• Test coverage for the proposed changes
• PR description contains example output from repl interaction or a snippet from unit test output
• Documentation has been updated if new natives or FV properties have been added. To generate new documentation, issue cabal run tests. If they pass locally, docs are generated.
• Any changes that could be relevant to users have been recorded in the changelog
• In case of changes to the Pact trace output (pact -t), make sure pact-lsp is in sync.

Additionally, please justify why you should or should not do the following:

• Confirm replay/back compat
• Benchmark regressions
• (For Kadena engineers) Run integration-tests against a Chainweb built with this version of Pact

[imalsogreg]

@jmcardon Think I should close this PR? Did we decide that all L2-related work will be against pact-core?

[imalsogreg]

@jmcardon Think I should close this PR? Did we decide that all L2-related work will be against pact-core?