support refreshing serverInfo metadata

[skeggse]

I'd like to suggest we add compatibility with NodeRedis w.r.t. the serverInfo object. NodeRedis updates the serverInfo object any time its client issues an INFO command to redis (and receives usable response) - see here. While it may incur extra overhead to do this every time if the resulting object is never read, it would be useful to provide an opt-in mechanism to allow updates to that metadata. In particular, this would allow other libraries that interoperate with NodeRedis to re-use the existing INFO parsing code without having to depend on another external library or embed INFO-parsing code in their internals for one supported library.

See also: bee-queue/arena#219

[marcbachmann]

The serverInfo object got removed in v5.
Application-level code should fetch the object itself.