SIlentOpenChest changes, HEX colors, stability improvements and bug fixes

• Added HEX colors. Format: #XXXXXX e.g.: '#663EF6This text would be purple!'
• SilentOpenChest changes and clarifications
  Now requires the permission sv.silentchest
  The error message in chat and in the console regarding a plugin loading another plugin's class should now be gone
  Vanished players will appear as spectators temporarily when they're opening chests silently. This is of course only the case for players who are allowed to see the vanished player. SV is required to switch players to spectator mode for them to open chests silently because of technical limitations. This is not new, it's just more visible now than in previous versions. The method I used back then doesn't work anymore and now causes error messages to appear in chat on many servers. Perhaps this will be fixed by ProtocolLib in the future so I can restore the old functionality without side-effects.
  Because players are being put into spectator mode temporarily it's best to only give the permission sv.silentchest to staff. While there are checks in place to make sure that this temporary spectator mode can't be abused, players will stay in spectator mode if the server has a hard crash while they are looking into the chest (and that can be abused).
• Many plugin stability improvements
• Action bars should now work on many more server versions
• Errors should no longer spam the console; they will only be displayed once
• Many errors will now contain information on what caused them and how they can be fixed