Rename progress to state in GrandExchangeOffer

The field formerly known as "progress" encoded what state the offer was
in which is a weird 4-bit thing that includes information about whether
the offer is a buy or sell offer, whether it's finished, and some other,
less well-defined info about (what seems to be) the offer's live-ness.
How close an offer is to being finished (ie its progress) is only really
based on how many items have bought/sold out of the total amount
requested/offered.

runescape-api/src/main/java/net/runelite/rs/api/RSGrandExchangeOffer.java

@@ -43,6 +43,7 @@ public interface RSGrandExchangeOffer
 	@Import("spent")
 	int getSpent();
 
-	@Import("progress")
-	byte getProgress();
+	@Import("state")
+	byte getRSState();
+
 }