Simplify the repo to the `proof-of-sql` crate once sqlparser adaptation is complete

[iajoiner]

Background and Motivation

This issue is a subtask in https://github.com/spaceandtimelabs/sxt-proof-of-sql/issues/235. In short since we plan to add more SQL features we plan to switch to the sqlparser crate which is a feature-rich, no_std-compatible parser used by DataFusion, which is part of the Arrow ecosystem.

Right now we already have some code that can convert intermediate AST from proof-of-sql-parser we use to sqlparser AST. Now we need to systematically replace instances of proof-of-sql-parser constructs with their corresponding sqlparser ones.

Changes Required

• [ ] Before we get started make sure that all previous issues are complete:
  • [x] #348
  • [x] #349
  • [ ] #350
  • [ ] #351
  • [ ] #352
  • [ ] #353
  • [ ] #354
  • [ ] #355
• [ ] Remove the workspace & the proof-of-sql-parser crate