Switch to using Authorization header for key

This is to switch to the new method to pass the secret key when getting data. The change to livedata was done in https://github.com/neutrons/live_data_server/pull/2

I tested this by setting my local dev build to use testfixture02-test.ornl.gov for livedata which has been updated to a new qa version that has the new method.

Ref 5923