feat: Adds configurable skill and stat gain (#1489)

### Summary

- Adds the following configurations:
```json
"stats.statMax": "125",
"stats.gainChanceMultiplier": 1.0,
"stats.primaryStatGainChance": 0.75,
"stats.gainDelay": "00:10:00",
"stats.petGainDelay": "00:05:00",
"stats.usePub45StatGain": "False"
```

- Adds Pub 45 stat gain rate for UOML+.
- Reduces the gain delay for legacy stat gain from 15 minutes to 10 minutes.
- Legacy gain no longer requires a gain in skill to gain in a stat.

Projects/Server/Configuration/ServerConfiguration.cs

@@ -64,6 +64,12 @@ public static class ServerConfiguration
         return bool.TryParse(strValue, out var value) ? value : defaultValue;
     }
 
+    public static TimeSpan GetSetting(string key, TimeSpan defaultValue)
+    {
+        _settings.Settings.TryGetValue(key, out var strValue);
+        return TimeSpan.TryParse(strValue, out var value) ? value : defaultValue;
+    }
+
     public static T GetSetting<T>(string key, T defaultValue) where T : struct, Enum
     {
         _settings.Settings.TryGetValue(key, out var strValue);