Tracer.startSpan should support overloads to parameterize messages

[carterkozak]

What happened?

We do a great deal of unnecessary string concatenation in span names which can be completely avoided for unsampled traces:

https://github.com/palantir/tracing-java/blob/c63567eacecc677c63db0f146fcd2f34493f2ffa/tracing-jersey/src/main/java/com/palantir/tracing/jersey/TraceEnrichingFilter.java#L62

https://github.com/palantir/tracing-java/blob/c63567eacecc677c63db0f146fcd2f34493f2ffa/tracing-okhttp3/src/main/java/com/palantir/tracing/okhttp3/OkhttpTraceInterceptor.java#L42

What did you want to happen?

Slf4j style overloads to construct trace strings only for sampled operations

[carterkozak]

Instead of parameterized methods we could take Supplier<String>.