webrtc: rename JSON-RPC streamID, componentID to streamId, componentId

Follow the same naming used in other similar properties, where "Id" is
used rather than "ID".

This was making direct JSON-RPC implementations very confusing because
some properties were using the "Id" style, while just these two were
using "ID".

src/server/interface/elements.WebRtcEndpoint.kmd.json

@@ -849,13 +849,13 @@ This could also happen in the middle of a session, though not likely.
  "doc": "The ICE candidate pair used by the ice library, for a certain stream.",
  "properties": [
  {
- "name": "streamID",
  "doc": "Stream ID of the ice connection",
+ "name": "streamId",
  "type": "String"
  },
  {
- "name": "componentID",
  "doc": "Component ID of the ice connection",
+ "name": "componentId",
  "type": "int"
  },
  {