Use TangoFTP instead of steam collection

[Extacy]

kzmaps.tangoworldwide.net is kept up to date by the KZ global team
Maps can become unavailable to download or play if steam is experiencing any issues
For a server operator there's hardly any benefits from using the workshop

[Gelmo]

Thank you for spending time on this; I had not yet gotten around to doing this. I'll test this out this weekend if I don't get around to doing so tonight.

[Gelmo]

Didn't get around to this tonight unfortunately, but will on Saturday.

[Gelmo]

@Extacy Sorry for the continued delays! I got the other PR merged into the develop branch and I'll push that to stable once I've tested from the Docker Hub image tonight.

In regard to this PR, I would like to implement the ability to remove deglobaled/updated maps, as well, before adding this to the image. That feature (removing deglobaled maps/versions) will need to be configurable with an ENV var, as there will be servers with non-global maps as well. That was an oversight on my part when I first added the DLMAPS var.

It's likely that I won't be able to work on that until Saturday, but I'll keep you informed. Feel free to work on it in the meantime, but I did already plan on implementing another var for that so don't feel obligated.