DRY work on app.iris_engine.reporter.reporter

[c8y3]

Method get_case_timeline seems to be duplicated in class IrisReportMaker (

iris-web/source/app/iris_engine/reporter/reporter.py

Line 157 in b3a36cd

def get_case_timeline(caseid):

) and in its subclass IrisMakeDocReport (

iris-web/source/app/iris_engine/reporter/reporter.py

Line 402 in b3a36cd

def get_case_timeline(caseid):

).
There are other methods which seem very similar in these two classes.
This file could be cleaned up somewhat. Probably by preferring composition and the strategy pattern over inheritance.