Integrate tCell into FireCloud UI

[davidangb]

This is a request from infosec: integrate the tCell library into the FireCloud UI.

from David Bernick:
can we get this JS in non-prod?
<script src="https://jsagent.tcell.io/tcellagent.min.js" tcellappid="FCNonprod-NaVu9" tcellapikey="AQEBBAEkx4iE2KxNyI7Wx08EwU1ycTM7E4FMSmaibbMUQxNU6uQvuAJt7fyABAtFYSYfgEE"></script>

and this one in prod?
<script src="https://jsagent.tcell.io/tcellagent.min.js" tcellappid="FCProd-EBOgM" tcellapikey="AQEBBAEGP2gTM2pIdJAQOIeNrm8dcTM7E4FMSmaibbMUQxNU6qy6nLPOBK8QfSvPFSsX8PQ"></script>

see also https://www.tcell.io/how-it-works/

Developer: make sure to check for any adverse interactions between tCell and New Relic and any other of our libraries.