Refactor: Reorganize testnet CLI functions

[carbolymer]

Description

This PR does not change any functions' bodies. The functions were only moved around and the modules were renamed.
Suggestion: The most efficient review process would be reviewing only modules' exports, how they changed.

cardano-testnet modules dependencies

Before:

After

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

Note on CI

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You will need to get someone with write privileges. Please contact IOG node developers to do this
for you.

[smelc]

Nice quality of life improvement 👍

[Jimbo4350]

Nice work. Much needed organization 👍