Feat: Add Support for schemars

[cappuccinocosmico]

Hey, I needed schemars support for some API documentation, and thought I should throw this back. Its totally optional if you dont want to merge it.

[MidasLamb]

Since, according to your commits, there seems to be a split in which version is used, I think it's a good idea to call the features according to the version, so for supporting of 0.9, the feature flag is schemars09 and for schemars 1.0 it would be schemars1. That way if new releases are cut of schemars, we can add support for it without breaking the version for older versions.

[cappuccinocosmico]

Awesome, I think that's a great way to handle it and just made the changes. My apologies for the delay, my GitHub notifications were turned off.