[CLI] Consistent config/flag parsing & common helpers

[bryanchriswhite]

@Reviewer

This PR may be more digestible / reviewable on a commit-by-commit basis. Commits are organized logically and any given line is only modified in a single commit, with few exceptions*.

(In the interest of preserving the git-time-continuum :police_officer::rotating_light:, this applies in batches of commits between comments or reviews by humans*, only once "in review")

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Description

I discovered some inconsistencies in how/whether we parse the config in different subcommands.

There was also some code that turns out to be common between some existing commands and the ones I'm adding for #730.

Issue

Related:

• 730

Dependents:

• 892

• 801

Type of change

Please mark the relevant option(s):

• [ ] New feature, functionality or library
• [ ] Bug fix
• [x] Code health or cleanup
• [ ] Major breaking change
• [ ] Documentation
• [ ] Other

List of changes

• simplified debug message broadcasting by using the p2p modules broadcast method
• factored out common CLI helper functions
  • FetchPeerstore()
  • GetBusFromCmd()
• ensured config and flag parsing is consistent
• ensured a consistent identity across subsequent usages of the debug CLI

Testing

• [ ] make develop_test; if any code changes were made
• [ ] make test_e2e on k8s LocalNet; if any code changes were made
• [ ] e2e-devnet-test passes tests on DevNet; if any code was changed
• [ ] Docker Compose LocalNet; if any major functionality was changed or introduced
• [x] k8s LocalNet; if any infrastructure or configuration changes were made

Required Checklist

• [x] I have performed a self-review of my own code
• [x] I have commented my code, particularly in hard-to-understand areas
• [ ] I have added, or updated, godoc format comments on touched members (see: tip.golang.org/doc/comment)
• [x] I have tested my changes using the available tooling
• [ ] I have updated the corresponding CHANGELOG

If Applicable Checklist

• [ ] I have updated the corresponding README(s); local and/or global
• [ ] I have added tests that prove my fix is effective or that my feature works
• [ ] I have added, or updated, mermaid.js diagrams in the corresponding README(s)
• [ ] I have added, or updated, documentation and mermaid.js diagrams in shared/docs/* if I updated shared/*README(s)