add link to performance data graph in service details

[nfilus]

Currently it is very annoying and resulting in too many mouse clicks to view the graph of performance data from service details. Only the Status graph is shown by default.

Use case:

Main Page -> problematic service -> service details

You see only changes OK <-> Warning <-> Critical, but often it is useful to take a look at the real data development. Currently one has to go to Views and click down until service found or go to Monitoring -> All Services -> find service -> enter through graph icon.