all: Add opentelemetry

This adds opentelemetry to the shared javadoc (but also other things
like having its tests contribute to code coverage).

all/build.gradle

@@ -15,6 +15,7 @@ def subprojects = [
     project(':grpc-inprocess'),
     project(':grpc-netty'),
     project(':grpc-okhttp'),
+    project(':grpc-opentelemetry'),
     project(':grpc-protobuf'),
     project(':grpc-protobuf-lite'),
     project(':grpc-rls'),

opentelemetry/build.gradle

@@ -41,3 +41,7 @@ tasks.named("compileJava").configure {
             ".*/build/generated/sources/annotationProcessor/java/.*",
             "|")
 }
+
+tasks.named("javadoc").configure {
+    exclude 'io/grpc/opentelemetry/internal/**'
+}