Separate tools from kernel module

[Mathias]

Hi Jason

Have you considered separating the WireGuard tools (src/tools) from the
kernel module itself?

The reasons being:

1. The tools are also used for configuring userspace implementations.
2. Work is ongoing on cross-platform WireGuard (e.g. experimental on
OSX), where the tools compile.
3. The kernel space implementation could in the future be configured by
different tools produced by 3rd parties.

Best Regards
Mathias