Allow for lazy-evaluation of arguments in LazyFormat

[plypaul]

When creating a LazyFormat object, the keyword argument values may be constructed from expensive methods. Similar to allowing a function to be passed in for the message argument, this PR enables methods to be passed in for the keyword argument values so that they can be lazily evaluated.

There were some logging calls that were found in performance profiling to be expensive because lazy-evaluation was not done, so this PR updates a few of those call sites as well. An alternative approach would have been to implement MetricFlowPrettyFormattable for those objects.