* Issue **gchq/stroom#2578** : Improve logging of Pipeline operations.


```sh
# ********************************************************************************
# Issue title: AppConfig instance variables need to be made `volatile`
# Issue link:  https://github.com/gchq/stroom/issues/2578
# ********************************************************************************

# ONLY the top line will be included as a change entry in the CHANGELOG.
# The entry should be in GitHub flavour markdown and should be written on a SINGLE
# line with no hard breaks. You can have multiple change files for a single GitHub issue.
# The  entry should be written in the imperative mood, i.e. 'Fix nasty bug' rather than
# 'Fixed nasty bug'.
#
# Examples of acceptable entries are:
#
#
# * Issue **123** : Fix bug with an associated GitHub issue in this repository
#
# * Issue **namespace/other-repo#456** : Fix bug with an associated GitHub issue in another repository
#
# * Fix bug with no associated GitHub issue.
```

Add change log file for update
Add change log file for update
