Config: Change ProcessPriority default to 0 (Normal)

On Linux, superuser (root) is required to set a process high priority and we shouldn't force that.
(It's already set to 0 (Normal) in worldserver\Master.cpp and authserver\Main.cpp)

src/server/authserver/authserver.conf.dist

@@ -82,11 +82,11 @@ UseProcessors = 0
 #
 #    ProcessPriority
 #        Description: Process priority setting for Windows and Linux based systems.
-#        Details:     On Linux, a nice value of -15 is used. On Windows, process is set to HIGH class.
-#        Default:     1 - (High)
-#                     0 - (Normal)
+#        Details:     On Linux, a nice value of -15 is used. (requires superuser). On Windows, process is set to HIGH class.
+#        Default:     0 - (Normal)
+#                     1 - (High)
 
-ProcessPriority = 1
+ProcessPriority = 0
 
 #
 #    RealmsStateUpdateDelay

src/server/worldserver/worldserver.conf.dist

@@ -160,11 +160,11 @@ UseProcessors = 0
 #
 #    ProcessPriority
 #        Description: Process priority setting for Windows and Linux based systems.
-#        Details:     On Linux, a nice value of -15 is used. On Windows, process is set to HIGH class.
-#        Default:     1 - (High)
-#                     0 - (Normal)
+#        Details:     On Linux, a nice value of -15 is used. (requires superuser). On Windows, process is set to HIGH class.
+#        Default:     0 - (Normal)
+#                     1 - (High)
 
-ProcessPriority = 1
+ProcessPriority = 0
 
 #
 #    Compression