Makes temporary permissions work

Saves and loads temporary permissions to/from disk as necessary
Gives players their temporary permissions when joining
Adds an un-used config file
Changes an english string in strings.yml

src/main/resources/config.yml

@@ -0,0 +1,5 @@
+# The language to use for the plugin
+language: en
+
+# Whether to only give permissions for a single world, instead of granting permissions for all worlds
+perWorldPermissions: false

src/main/resources/strings.yml

@@ -13,7 +13,7 @@ en:
   COMMAND_PERMISSION_DENIED: "&7You do not have necessary permissions to perform this command"
   CREATION_REQUEST_CREATED: "&7Permission Sign request created. Right-click an empty sign within 60 seconds to create the new permission sign"
   CANNOT_AFFORD: "&7You cannot afford to use this permission sign"
-  ALREADY_HAS_PERMISSIONS: "&7You already have all permissions sold by this permission sign"
+  ALREADY_HAS_PERMISSIONS: "&7You already have all permissions given by this permission sign"
   PERMISSIONS_GRANTED: "&7You have been granted the following permission nodes: {permissions} for {time}"
   PERMISSION_SIGN_CREATED: "&7Permission sign successfully created!"
   CREATION_REQUEST_CANCELLED: "&7Your last permission sign creation request has been cancelled"