Add TimeMap in the comparison table

We regularly have users comment on the usefulness of perfSONAR if TimeMap is deployed in the network. It would be useful to clarify the differences between the 2 tools in our comparison table at https://www.perfsonar.net/gtk_comparison.html

TimeMap is described at https://network.geant.org/timemap/

Some differences that should be highlighted are:

• TimeMap is for the core network, measuring on network segments only, whereas perfSONAR is for the end-to-end measurements
• TimeMap is only doing latency and jitter measurements, perfSONAR metrics cover a more comprehensive range of network characteristics
• TimeMap automatically analyses the measurements to spot deviations, perfSONAR data analysis must be done externally
• TimeMap aims at giving helpful information for time-sensitive applications whereas perfSONAR is most useful for data-intensive applications
• TimeMap is meant to be used by network operators, perfSONAR is used by both network operators and end users
• TimeMap is restricted to a single network, perfSONAR operates across networks in a multi-domain setting.

Open the comparison table at https://www.perfsonar.net/gtk_comparison.html and review the TimeMap description at https://network.geant.org/timemap/. Update the table to cover the six listed differences in scope, metrics, analysis, audience, and network coverage, then verify the rendered page and links.