Add a configurable way to mask sensitive information

[joe94]

One of our community members reported in xmidt-org/xmidt#51 that it would be nice having a way to mask sensitive information such as device IDs (information that could be traced back to an individual customer) from log entries.

Some of the log field names that include sensitive data across our microservices are:
requestURL
requestURI
requestHeaders.Referer
instance

Suggested Approach
Compile a global regex to match device IDs from within a string and replace all characters with a * except the prefix. Ex: mac:1122334455 would become mac:**********

Configuration:

log:
  ...
  # defaults to false meaning sensitive data is masked by default
  disableSensitiveDataMasking: false