fix tokio thread_name

[rukai]

pulled out of and continuing discussion from #1315 (comment)

After enabling "show custom thread names" in htop (its disabled by default) we get output like this:

It looks truncated because linux does not support thread names that long.

This PR fixes the issue by using a shorter thread name.
It now looks like this:

While there could theoretically be some obscure case out there, at our current scale I dont believe this will cause any issues due to the change of name.
Scripts that invoke things like killall shotover-proxy will be unaffected because the main thread is still called shotover-proxy.

[conorbros]

Scripts that invoke things like killall shotover-proxy will be unaffected because the main thread is still called shotover-proxy.

I hadn't considered this when I raised that original point, thanks for pulling out though. LGTM.

[cjrolo]

Approving, but relying on htop as the go-to tool to identify processes is not always the best. I mostly rely on ps for that if working on a server\server tools. For those tools I don't thing we would have limitations on naming size. But I do prefer the shorter name.

[rukai]

It is the Linux API that limits to 16 characters not htop https://man7.org/linux/man-pages/man3/pthread_setname_np.3.html