MINOR: config: Support partial ranges in cpu-map directive

MINOR: config: Support partial ranges in cpu-map directive

Now, processa and CPU ranges can be partially defined. The higher bound can be
omitted. In such case, it is replaced by the corresponding maximum value, 32 or
64 depending on the machine's word size.

By extension, It is also true for the "bind-process" directive and "process"
parameter on a "bind" or a "stats socket" line.