[Feature] Add support for all Vault-based permission plugins

This commit adds vault permission and chat support as a backup to the existing permission handling. This allows servers to use Vault-based permission plugins that aren't explicitly supported by Essentials.
@chrisgward as far as I know, there isn't any building API in Vault, so I just mimicked the behavior of the SuperpermsHandler (https://github.com/essentials/Essentials/blob/2.x/Essentials/src/com/earth2me/essentials/perm/SuperpermsHandler.java#L24)