feat: opentelemetry integration, removed self designed tracing (#1111)

* feat: opentelemetry integration, removed self designed tracing

* feat: support zipkin on opentelemetry integration

* feat: support zipkin on opentelemetry integration, enable it in conf

* style: format code

* fix: support logx without exporter configured

* fix: check return values

* refactor: simplify code

* refactor: simplify opentelemetry integration

* ci: fix staticcheck errors

core/trace/config.go

@@ -0,0 +1,12 @@
+package trace
+
+// TraceName represents the tracing name.
+const TraceName = "go-zero"
+
+// A Config is a opentelemetry config.
+type Config struct {
+	Name     string  `json:",optional"`
+	Endpoint string  `json:",optional"`
+	Sampler  float64 `json:",default=1.0"`
+	Batcher  string  `json:",default=jaeger,options=jaeger|zipkin"`
+}