Add tool to combine pre-migration and post-migration reports

Add utility config-assessment-tool-combiner.py and maintain it version to version. Consider support for older versions, and document the limitation, eg only combines version n-1 and current version n.

[https://appdynamics.slack.com/archives/C02G06M4X61/p1647905577901539](url)

Start by reviewing the existing report formats and versioning approach in the repository before adding config-assessment-tool-combiner.py. Define how pre-migration and post-migration reports are combined, assess support for older versions, and document any limitation such as supporting only version n-1 with the current version.

Written by the indexing model from the issue text.