Hotfix sql spigot link

[Wyzards]

Story Title

This is the Issue Title

Changes made

• Replaced previous spigot HikariConfig code with working velocity config code
• Fixes documentation
• Creates GrubnestPlayer interface, to implement a Custom player object across Spigot & Velocity
• Moves all database access methods to MySQL class
• Implements VPlayer object, which represents Custom Players on the Velocity server

How does the solution address the problem

This PR's main feature, replacing the HikariConfig code from Spigot with the one used from Velocity, prevents the communications link failure on the Spigot server. It still works correctly on Velocity as well.