feat(stdlib): add encode_charset, decode_charset functions

[powerumc]

Summary

Charset encoding and decoding functions were implemented to integrate the charset settings used in various operating systems and systems with vector.

• decode_charset(value, from_charset)
• encode_charset(value, to_charset)

Change Type

• Bug fix
• New feature
• Non-functional (chore, refactoring, docs)
• Performance

Is this a breaking change?

• Yes
• No

How did you test this PR?

• decode_charset unit test
• encode_charset unit test

Does this PR include user facing changes?

• Yes. Please add a changelog fragment based on
  our guidelines.
• No. A maintainer will apply the "no-changelog" label to this PR.

Checklist

• Our CONTRIBUTING.md is a good starting place.
• If this PR introduces changes to LICENSE-3rdparty.csv, please
  run dd-rust-license-tool write and commit the changes. More details here.
• For new VRL functions, please also create a sibling PR in Vector to document the new function.
  • vectordotdev/vector #21981

PR adding new VRL function:

• decode_charset function
• encode_charset function

PR adding documentation:

• 1162.feature.md

References

• Closes: feat(stdlib): Function for Converting Character Encodings #1155

[pront]

Thank you @powerumc!

Left a couple of minor comments.

[powerumc]

@pront
I submitted a sibling PR in Vector to document the new function. vectordotdev/vector #21981
Thank you for your review. 😊

[pront]

The licenses check fails, please use dd-rust-license-tool write && git commit -am "dd-rust-license-tool write" and push to fix.

[powerumc]

The licenses check fails, please use dd-rust-license-tool write && git commit -am "dd-rust-license-tool write" and push to fix.

In my case, there is no change in the dd-rust-license-tool write and commit -am "dd-rust-license-tool write" command.
the check-licenses step in GitHub Actions was successful.

The error occurs in the check-deny step. Is this caused by my code?
https://github.com/vectordotdev/vrl/actions/runs/12160810717/job/34141068366?pr=1162

[jszwedko]

I think we just needed main merged in to fix the cargo deny failure. I merged it here.