Add Xtensa arch support

[b1llow]

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Your checklist for this pull request

• [ ] I've read the guidelines for contributing to this repository
• [ ] I made sure to follow the project's coding style
• [ ] I've documented or updated the documentation of every function and struct this PR changes. If not so I've explained why.
• [ ] I've added tests that prove my fix is effective or that my feature works (if possible)
• [ ] I've updated the rizin book with the relevant information (if needed)

Detailed description

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Test plan

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Closing issues

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[XVilka]

Probably makes sense to rebase on top of the https://github.com/rizinorg/rizin/pull/4662 to avoid conflicts and double work. cc @Rot127

[Rot127]

Yes, though let's wait until the Capstone PRs are merged.

[XVilka]

OK, LGTM now, just lets wait first for the Capstone PR to be merged first.