[feature] Added node/link highlighting#371

mwarning wants to merge 2 commits intoopenwisp:163-gsoc22-example-with-nodelink-highlightingopenwisp/netjsongraph.js:163-gsoc22-example-with-nodelink-highlightingfrom

mwarning:selectionmwarning/netjsongraph.js:selectionCopy head branch name to clipboard