Add automatic database seed fetching based on connection string and hashed seed

[xpple]

As it is currently implemented, if there is a database match, the seed will be sent to the player every time they log in or respawn. If this is too annoying, it can be changed to only do so on log ins. However this may have the issue that when the nether has a different seed, it won't be communicated to the player.

Some notes:

• I added DevAuth to be able to easily test on multiplayer servers. A server that currently works as a nice example of this feature is java.donutsmp.net.
• The version is currently ignored when fetching the database, this can be changed if necessary.
• The database URL for fetching the seeds is currently CSV-based, so far it has worked fine but perhaps it can be replaced with a script if necessary.

[19MisterX98]

thx