Bump iohk-monitoring - drop dependency on snap

[mgmeier]

Description

This PR:

1. bumps iohk-monitoring to a version that replaces the snap server beckend with wai / warp.
2. switches all remaining build targets in the repo from snap-based ekg to ekg-wai.
3. sensibly constrains ekg-forward (0.5 contains a space leak, and 0.7 will contain breaking changes).

This ultimately removes snap-server from node dependency graph entirely.

Checklist

• Commit sequence broadly makes sense and commits have useful messages
• New tests are added if needed and existing tests are updated. These may include:
  • golden tests
  • property tests
  • roundtrip tests
  • integration tests
    See Runnings tests for more details
• Any changes are noted in the CHANGELOG.md for affected package
• The version bounds in .cabal files are updated
• CI passes. See note on CI. The following CI checks are required:
  • Code is linted with hlint. See .github/workflows/check-hlint.yml to get the hlint version
  • Code is formatted with stylish-haskell. See .github/workflows/stylish-haskell.yml to get the stylish-haskell version
  • Code builds on Linux, MacOS and Windows for ghc-8.10.7 and ghc-9.2.7
• Self-reviewed the diff

[erikd]

LGTM