Improve bStats metrics

[Andre601]

Pull Request

Type

• Internal change (Doesn't affect end-user).
• External change (Does affect end-user).
• Wiki (Changes towards the Wiki).
• Other: __________

Description

Closes N/A

This PR changes a few things.
It first of all changes the Version class to have a nested Type Enum which is used in the static of PlaceholderAPIPlugin to determine the actual server type used.

The code to do this has been borrowed from the Server-Expansion and currently supports Purpur, Tuinity, PaperMC and Spigot itself.

Next does using_spigot now return 3 different responses:

• yes (fork) when it is a Spigot fork (Currently PaperMC, Tuinity and Purpur)
• yes for Spigot itself
• no for any other cases

All forks are currently treated as isSpigot = true, so if that should be changed, let me know.

The original Version(String, boolean) Constructor has been deprecated in favour of the Version(String, Version.Type) Constructor, but still works, with the class resulting in having Version(version, Type.SPIGOT) set when server is a Spigot server and Version(version, Type.UNKNOWN) when it is not.

Important
A new SimplePie Chart has been added. The identifier is server_brand and it returns the Server Brand name, so a new Chart would need to be added to bStats to have these metrics working.

[Andre601]

I decided to now have the server brand as its own SimplePie Chart with the identifier server_brand, so if this gets merged should the Metrics on bStats receive a new chart with that identifier.

Additionally does using_spigot now return yes (fork) when the Server brand is a fork of Spigot (Currently everything except Spigot and Unknown). It will otherwise either return yes for normal Spigot Server or no in any other case.

[Andre601]

This won't be added in the near future, so I just close this.