yeah all the packages configs will stay the same.. No 2.2.2 to 2.2.5 is not a major release, 2.1.x to 2.2.x would be a major update. Normally they mention if major changes in the release notes. For example the upcoming 2.3 going to be major changes. But even then prob no need to uninstall the packages unless its a problematic one.. Make sure you read the release notes on an update, wait a few days and read the forums on other peoples experiences with the update if your concerned and this is critical production system, etc.
https://blog.pfsense.org/?cat=53
Upgrade Guidance
As always, you can upgrade from any previous version straight to 2.2.5. For those already running any 2.2.x version, this is a low risk upgrade. For those on 2.1.x or earlier versions, there are a number of significant changes which may impact you. Pay close attention to the 2.2 Upgrade Notes for the details.