Notify when system.xml changes

[convenient]

Work similar to #67 could be done to actually analyse when config values are added or deleted to magento.

Might be useful information although it may be a deluge to have by default, so maybe hidden behind a flag would be useful

Context

Maybe similar logic can be used for discovering changes in other type of xml files (like adminhtml/system.xml to see if configuration settings were added/removed). Just an idea, not sure if really helpful
#67 (comment)

neat idea @hostep this kind of thing is definitely now possible, but I wonder how much noise we'd get for how much value? I fear the payment methods and third party modules magento bundles / unbundles would cause this to be loud? 🤔
#67 (comment)

True, but the behavior could maybe be hidden behind a flag? --also-show-config-changes (I'm bad at naming things, so this is probably not the best option)
#67 (comment)