Fix default Inventory messages.
Update refresh interval
Added an Arrays utility for resolving issues involving java 11.
Fix grammar mistakes in GUI's.
Fixed the plugin version not being displayed upon doing /pm command
Fixed an error produced when switching from java 11 to java 8 (Optional#isEmpty doesn't exist)
Compiling the plugin with java 8 to ensure the plugin is compatible with both 1.8.8 and 1.19 versions
Added a placeholder option for "%pm_{plugin}_soft%
Changed the short description of the plugin.
Changed API version back to 1.13 in order for the server to support versions lower than 1.17
