CLC-4240 Reduce number of SLOW warnings in log files

… but improve our coverage of slow responses from CalCentral. This should make the morning production audit emails easier to read.

https://jira.ets.berkeley.edu/jira/browse/CLC-4240

@raydavis as you mentioned in the jira, this seems like a very high number. Do we already have a jira to ask the API producers of these slow queries to look at the performance?