chore(stdlib)!: remove unnecessary merkle functions from stdlib

[TomAFrench]

Description

Problem*

Related to #1258 and noir-lang/acvm#295

Summary*

This PR removes the unnecessary functions from the merkle module in the stdlib (check_membership and compute_root_from_leaf).

We no longer use the black box version of compute_merkle_root in preparation for the opcode being removed and just use the noir implementation (which has been shown to be more efficient anyway). compute_root_from_leaf is then removed/renamed to compute_merkle_root

Documentation

• This PR requires documentation updates when merged.

  • I will submit a noir-lang/docs PR.
  • I will request for and support Dev Rel's help in documenting this PR.

Additional Context

PR Checklist*

• I have tested the changes locally.
• I have formatted the changes with Prettier and/or cargo fmt on default settings.

[critesjosh]

Has check_membership been removed in favor of just computing the root and comparing to a given root. If they match, then it's a member?

[TomAFrench]

Yes, that's correct. We expect user code to use assert(expected_root == compute_merkle_root(...)) instead of wrapping it in an extra function.