Resource provider regeneration

Implemented resource regeneration computation in the
verse.compute_provider_regeneration() function.

Created the PLANET_RES_REGEN update type, and added the corresponding
implementation.

Added resource regeneration constants registration.

legacyworlds-server-data/db-structure/parts/data/000-typedefs.sql

@@ -28,20 +28,53 @@ CREATE TYPE log_type
 
 -- Update types
 CREATE TYPE update_type	AS ENUM (
+
+	/* Empires' money is being updated using the previous update's results */
 	'EMPIRE_MONEY' ,
+	
+	/* Empire research points are being attributed to technologies */
 	'EMPIRE_RESEARCH' ,
+	
+	/* The effects of empires' debts are being computed */ 
 	'EMPIRE_DEBT' ,
+	
+	/* Fleets which were 1 update away are arriving at their destination */
 	'PLANET_FLEET_ARRIVALS' ,
+	
+	/* Other fleets are moving */
 	'PLANET_FLEET_MOVEMENTS' ,
+	
+	/* Fleet states (e.g. "deploying", "unavailable", etc...) are being
+	 * updated.
+	 */
 	'PLANET_FLEET_STATUS' ,
+	
+	/* Start new battles where necessary */
 	'PLANET_BATTLE_START' ,
+	
+	/* Process all in-progress battles */
 	'PLANET_BATTLE_MAIN' ,
+	
+	/* Finalise battles that need to be ended */
 	'PLANET_BATTLE_END' ,
+	
+	/* Abandon planets */
 	'PLANET_ABANDON' ,
+	
+	/* Handle civilian build queues */
 	'PLANET_CONSTRUCTION' ,
+	
+	/* Handle military build queues */
 	'PLANET_MILITARY' ,
+	
+	/* Update planets' population */
 	'PLANET_POPULATION' ,
-	'PLANET_MONEY' 
+	
+	/* Regenerate resources in resource providers */
+	'PLANET_RES_REGEN' ,
+
+	/* Compute income and upkeep of planets */
+	'PLANET_MONEY'
 );
 
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