feat(cpp/conf): Add option to teach all spells on first login (#9)

- Adds a `LearnAllOnFirstLogin` (default: false) option to teach the
player all the spells when he first logs in,
- Disabled by default because of performance concerns,
- Slight optimizations have been added to mitigate this issue
- However enabling this on a more populous server could cause issues
due to the current design of the module

conf/mod_learnspells.conf.dist

@@ -12,6 +12,12 @@ LearnSpells.Enable = 1
 
 LearnSpells.Announce = 1
 
+# Should the player receive all spells on first login?
+# Useful for instant leveling type of servers
+# (1: true | 0: false)
+
+LearnSpells.LearnAllOnFirstLogin = 0
+
 # Max level Limit the player will learn spells
 # 	Default:  = 80