Change all core config paths to use CorePath enums

[Rumsfield]

The hard-coded String paths must be replaced with their counterpart enums in CorePath. Throughout the code, core.yml options are fetched using this common approach:

refreshTimeSeconds = konquest.getConfigManager().getConfig("core").getLong("core.monuments.loot_refresh",(long)0.0);

Most major classes have a reference to the main Konquest instance, konquest, either directly or via a superclass method getKonquest(). Core.yml settings are loaded into memory on plugin enable, and are accessed via the ConfigManager class, which can access the core config. Because this is so common, there is a convenience method, Konquest#getCore().

So, there are two changes for every occurrence of this core config access:

1. Replace konquest.getConfigManager().getConfig("core") with konquest.getCore().
2. Replace the String path with its corresponding enum, e.g. "core.monuments.loot_refresh" with CorePath.MONUMENTS_LOOT_REFRESH.getPath().

Search for all occurrences of getConfigManager().getConfig("core") to find most of these areas. If any String paths do not have a matching CorePath enum, leave it alone and record its location in this issue.

[Rumsfield]

I'm going to do this in branch #35.