[experimental] Query Engine workstream

[drewrelmas]

This issue tracks development in the Rust experimental folder regarding:

• A parser mechanism to translate 'query language statements' from multiple sources (OTTL, KQL, etc...) into a uniform intermediate representation
  • Started in Init of query_abstractions sub-project for Transform #316
• A 'query engine' component that can use that intermediate representation to normalize/filter/aggregate data, preferably taking advantage of the Arrow format central to this repository
  • Started in [query-engine] KQL accessor support #542

The eventual vision is using this 'query engine' as a processor in an OTAP pipeline that can accept a variety of transform language inputs while sharing a single implementation internally to do the actual data manipulation.

[jmacd]

I see this query engine also as an opportunity to explore what OpenTelemetry calls the "Views" interface for SDKs. OpenTelemetry defines a Views mechanism for its Metrics SDK but not for its Spans/Logs SDK. 🚀