[7zip] Add C headers to includes

[judemille]

The current 7zip port only adds the CPP headers to the includes. This PR adds the C headers, for consumers that need that.

• Changes comply with the maintainer guide
• SHA512s are updated for each updated download (not applicable)
• The "supports" clause reflects platforms that may be fixed by this new version (not applicable)
• Any fixed CI baseline entries are removed from that file. (no changes here)
• Any patches that are no longer applied are deleted from the port's directory. (no changes)
• The version database is fixed by rerunning ./vcpkg x-add-version --all and committing the result.
• Only one version is added to each modified port's versions file.

The 7zip version 23.01 has been overridden. This can be changed if necessary.

[Osyotr]

The 7zip version 23.01 has been overridden. This can be changed if necessary.

Please bump port-version. https://github.com/microsoft/vcpkg-docs/blob/main/vcpkg/contributing/maintainer-guide.md#update-the-port-version-field-in-the-manifest-file-of-any-modified-ports

[Osyotr]

This is not supposed to change. I'm not sure what's the easiest way to fix this, but I would revert changes in this file and baseline.json and then call vcpkg x-add-version 7zip

[judemille]

Fixed that. Will squash commits if desired, though I'm not sure how that can be done in a manner that keeps vcpkg happy.

[Osyotr]

PRs in this repo are automatically squashed when merged. Note that these values are not commit hashes, but git tree hashes.

[judemille]

Ah, I see.

[judemille]

CLA agreed to, begrudgingly.