refactor!: rename functions, API to CometBFT

[julienrbrt]

Description

Blocked on #14897
ref: #14870, #14897

This is a PR that rename all commands to API to cometbft and mention of Tendermint Core in the code and docs.
Aliases will be set in place to stay minimally breaking.

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Author Checklist

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I have...

• included the correct type prefix in the PR title
• added ! to the type prefix if API or client breaking change
• targeted the correct branch (see PR Targeting)
• provided a link to the relevant issue or specification
• followed the guidelines for building modules
• included the necessary unit and integration tests
• added a changelog entry to CHANGELOG.md
• included comments for documenting Go code
• updated the relevant documentation or specification
• reviewed "Files changed" and left comments if necessary
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• confirmed the correct type prefix in the PR title
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• reviewed state machine logic
• reviewed API design and naming
• reviewed documentation is accurate
• reviewed tests and test coverage
• manually tested (if applicable)

[julienrbrt]

Closing this for now, I will keep migrating main in a non-breaking way in #14914 (renaming of imports and stuff).
I want to discuss in our standup up to which point we want to be breaking.