initial jaeger integration (#2047)

Co-authored-by: Pierre Krieger <pierre.krieger1708@gmail.com>
Co-authored-by: Peter Goodspeed-Niklaus <coriolinus@users.noreply.github.com>
Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

polkadot/cli/src/cli.rs

@@ -91,6 +91,13 @@ pub struct RunCmd {
 	/// elapsed (i.e. until a block at height `pause_block + delay` is imported).
 	#[structopt(long = "grandpa-pause", number_of_values(2))]
 	pub grandpa_pause: Vec<u32>,
+
+	/// Add the destination address to the jaeger agent.
+	///
+	/// Must be valid socket address, of format `IP:Port`
+	/// commonly `127.0.0.1:6831`.
+	#[structopt(long)]
+	pub jaeger_agent: Option<std::net::SocketAddr>,
 }
 
 #[allow(missing_docs)]
@@ -98,7 +105,6 @@ pub struct RunCmd {
 pub struct Cli {
 	#[structopt(subcommand)]
 	pub subcommand: Option<Subcommand>,
-
 	#[structopt(flatten)]
 	pub run: RunCmd,
 }