Add New Relic instrumentation to SequenceModule.
Add New Relic instrumentation to SequenceModule.

The goal of this is to capture more detailed usage and performance
information around the kind of course content we have out there.
Having this information will allow us to more easily query to see
how sequence size and specific block types affect front end
performance.

bmedx/modulestore,bmedx/modulestore,bmedx/modulestore