Remove parachain-id cli command (#739)

This was never planned to be a permanent feature. This was mainly added for testing purposes, but
now was copied by everybody. The users should be more specific about the para id and set this
properly in the chain spec.

cumulus/parachain-template/node/src/cli.rs

@@ -46,12 +46,6 @@ pub struct ExportGenesisStateCommand {
 	#[structopt(parse(from_os_str))]
 	pub output: Option<PathBuf>,
 
-	/// Id of the parachain this state is for.
-	///
-	/// Default: 100
-	#[structopt(long, conflicts_with = "chain")]
-	pub parachain_id: Option<u32>,
-
 	/// Write output in binary. Default is to write in hex.
 	#[structopt(short, long)]
 	pub raw: bool,