feat(core): Move async propagation API from scope to tracer

Author: PerfectSlayer

dd-trace-core/src/test/groovy/datadog/trace/core/scopemanager/ScopeManagerTest.groovy

@@ -27,7 +27,6 @@ import java.util.concurrent.TimeUnit
 import java.util.concurrent.atomic.AtomicInteger
 import java.util.concurrent.atomic.AtomicReference
 
-import static datadog.trace.bootstrap.instrumentation.api.AgentTracer.setAsyncPropagationEnabled
 import static datadog.trace.core.scopemanager.EVENT.ACTIVATE
 import static datadog.trace.core.scopemanager.EVENT.CLOSE
 import static datadog.trace.test.util.GCUtils.awaitGC