Refactor/deprecate trace config (open-telemetry#2303)

Author: pitoniak32

traces.rs

@@ -23,7 +23,7 @@ mod throughput;
 
 lazy_static! {
     static ref PROVIDER: sdktrace::TracerProvider = sdktrace::TracerProvider::builder()
-        .with_config(sdktrace::Config::default().with_sampler(sdktrace::Sampler::AlwaysOn))
+        .with_sampler(sdktrace::Sampler::AlwaysOn)
         .with_span_processor(NoOpSpanProcessor {})
         .build();
     static ref TRACER: sdktrace::Tracer = PROVIDER.tracer("stress");