Consume Weaver schema files

[martincostello]

I recently only learned that Weaver (specifically Live Check) can be used to create schemas that define what telemetry being emitted by an application is valid.

I wondered whether that's something we could make OATS take into account when testing an application's metrics if a schema file is provided, assuming it's useful and not too much effort.

It would probably be only worth doing if we can do a minimal pass without doing to much custom code, otherwise the user should just additionally run Weaver as well as OATS as we'd basically just be duplicating Weaver in OATS (or just bundling it and including it).