Use jsonschema-rs for request/response validation

[playpauseandstop]

jsonschema-rs in theory should allow rororo dramatically improve request/response validation speed.

As of 0.1.0 version error handling is not there, but it is still good idea to prepare basis for drop-in replacement for request/response validation via faster jsonschema alternative.

[playpauseandstop]

As of https://twitter.com/Stranger6667/status/1271075766835576832,

JSONSchema.validate method is implemented in 0.3.0. It raises ValidationError :) Quite similar to jsonschema lib behavior. Iterator over errors will be implemented soon