[skip changelog] Fix core commands skipping gRPC interface

[silvanocerza]

Please check if the PR fulfills these requirements

• The PR has no duplicates (please search among the Pull Requests
  before creating one)
• The PR follows our contributing guidelines
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)
• UPGRADING.md has been updated with a migration guide (for breaking changes)

• What kind of change does this PR introduce?

Refactors some commands internals.

• What is the current behavior?

cli/core commands are currently calling commands/core function without using rpc Requests structs.

• What is the new behavior?

All cli/core commands now call commands/core functions using the rpc Requests structs.

• Does this PR introduce a breaking change, and is titled accordingly?

Nope.

• Other information:

We don't fix any issue with this PR but we'll avoid breaking the CLI and the gRPC interface alignment.

This adds more output to core list --format json but it doesn't break anything.

This change started out from a comment by @cmaglie on #1166, we should rebase that branch on top of this and another subsequent PR that will fix some legacy tests to verify that hardware loading works as expected.

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[cmaglie]

LGTM