feat: Add OTLP log endpoints (gRPC & HTTP)

[MikeGoldsmith]

Which problem is this PR solving?

Adds support for receving OTLP logs. Only logs with a trace ID associated are handled and are sampled along with spans. Logs without a trace ID are forwarded to Honeycomb immediately like events without TraceIDs are.

Further work to add support for configurable correlation IDs will be done in later PRs.

Note: This is the 2.x version of adding OTLP Logs, see the following PR that tracks adding to 3.x on main branch:

• feat: Add OTLP log endpoints (gRPC & HTTP) #1168

Short description of the changes

• Add OTLP endpoints gRPC & HTTP (http/proto & http/json) including support for gzip & zstd
• Adds missing API key check for trace gRPC handler with tests
• Add unit tests to verify endpoints and different encodings are handled
• Add unit tests to verify logs with a Trace ID are added to collector and logs without a Trace ID are sent to libhoney for dispatch
• Rename processTraceRequest to processOTLPRequest and use in otlp_trace
• Rename OTLP trace endpoint func postOTLP to postOTLPTraces
• Add MockCollector to aid with testing

[kentquirk]

This looks really good! One very minor nit.