no subdirectories command line option added (#214)

added command line option to not create timestamped directories for test
runs.

# Checklist

The following aspects have been respected by the author of this pull
request, confirmed by both pull request assignee **and** reviewer:

* Adherence to coding conventions
  * [x] Pull Request Assignee
  * [x] Reviewer
* Adherence to javadoc conventions
  * [x] Pull Request Assignee
  * [x] Reviewer
* Changelog update (necessity checked and entry added or not added
respectively)
  * [x] Pull Request Assignee
  * [x] Reviewer
* README update (necessity checked and entry added or not added
respectively)
  * [x] Pull Request Assignee
  * [x] Reviewer
* config update (necessity checked and entry added or not added
respectively)
  * [x] Pull Request Assignee
  * [x] Reviewer
* SDCcc executable ran against a test device (if necessary)
  * [x] Pull Request Assignee
  * [x] Reviewer

CHANGELOG.md

@@ -11,6 +11,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - support for Kotlin
 - preconditions which observe mdib changes during the test run
 - storing of IP addresses of inbound messages in the database
+- a command line parameter to not create subdirectories in the test run directory
 
 ### Changed