feat(code): Allow applications to define their own configuration type

[romac]

Closes: #852

This PR removes the global malachite_config::Config struct and instead lets applications define their own configuration type with only the settings they need, which can include some of the settings provided by malachite_config, e.g. ConsensusConfig, DiscoveryConfig, etc. Some of those are required, and are captured by the new NodeConfig trait. This also enables applications to pick a configuration format other than TOML.

To this end, the Node trait gains an additional abstract type member, Node::Config, to be instantiated with the concrete configuration type.

Most of the complexity in this PR was to adapt the CLI and the test framework to deal with the new abstract configuration type defined by the application via the Node trait instead of working with a concrete Config type.

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PR author checklist

For all contributors

• Reference GitHub issue
• Ensure PR title follows the conventional commits spec

For external contributors

• Maintainers of Malachite are allowed to push changes to the branch

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 81.99%. Comparing base (ad7350e) to head (25241b6).

✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #872      +/-   ##
==========================================
- Coverage   82.64%   81.99%   -0.65%     
==========================================
  Files         187      189       +2     
  Lines       16088    16150      +62     
==========================================
- Hits        13295    13242      -53     
- Misses       2793     2908     +115     

Flag	Coverage Δ
integration	81.86% <ø> (-0.65%)	⬇️
mbt	8.30% <ø> (-0.13%)	⬇️

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Components	Coverage Δ
core	∅ <ø> (∅)
engine	∅ <ø> (∅)
app	∅ <ø> (∅)
starknet	∅ <ø> (∅)