Performance tune v1.0.0-RC branch

The upgrade to Django 2.2 and webhooks rewrite on the v0.8 have greatly degraded the performance of Simpl model services. Performance tuning is needed to correct this problem.

Running two Simpl profiler 312 player login tests of the Wharton ROE simulation against the Wharton dev simpl-games-api v0.8.3 server took 579.616s and 577.427s. Running the same tests against the Wharton dev simpl-games-api v0.7.22 server took 186.102s and 183.697s. The v0.8 code is over 3 times slower than the v0.7 code.

The Wharton Learning Lab roe-model README contains complete instructions for running this Simpl profiler test. Rerunning this test against the Wharton dev simpl-games-api can be used to gauge progress in correcting this problem.

[joelee484]

Based on discussions yesterday, @frankwiles will take a first pass at this by implementing the batching of webhook messages. This should lead to a dramatic increase in performance that hopefully brings the platform in-line with the Thorn-based version of Simpl (pre v0.8).