Create nfssrvutil.d

Description: This script measures the percentage of NFS thread pool currently utilized 
(maximum being NFSD_SERVERS), along with Max pending (queued) NFS requests that have not 
yet been assigned a thread. It is useful in troubleshooting bottlenecks in the Solaris  
NFS server, and determining the correct NFSD_SERVERS value for high-load systems.