Improved metadata handling

[regbo]

I created a library that allows for compositemetadata to be used:
https://github.com/regbo/lfp-rsocket-ipc-metadata

It comes with a few other features, but I think the method used could be used here to improve current support. Have a look and LMK if you ave any questions.

[OlegDokuka]

Hey @regbo.

Work on CompositeMetadata support is done in #44 PR.
As of now, I don't have enough time to finalize it but in general, it is ready to be used.

Feel free to check out and test is locally

[regbo]

Awesome thanks!

[OlegDokuka]

If you see how to improve the existing project, feel free to contribute.

PRs are welcome

[regbo]

Hi @OlegDokuka I created a PR (#63)