rename portid and port prefix for interchain accounts submodules (cos…

…mos#779)

## Description

I decided to remove the `-` from the port ID (`ica-host`) and prefix (`ica-controller`) and just make it one word (`icahost` and `icacontroller`), just in case we decide to do some parsing based on a `-` delimiter in the future.

closes: cosmos#778 

---

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modules/apps/27-interchain-accounts/types/keys.go

@@ -9,10 +9,10 @@ const (
 	ModuleName = "interchainaccounts"
 
 	// PortID is the default port id that the interchain accounts host submodule binds to
-	PortID = "interchain-account"
+	PortID = "icahost"
 
 	// PortPrefix is the default port prefix that the interchain accounts controller submodule binds to
-	PortPrefix = "ics27-"
+	PortPrefix = "icacontroller-"
 
 	// Version defines the current version for interchain accounts
 	Version = "ics27-1"