update core open-rewrite to the latest version

[martinlippert]

In order to address #1641, we need to update the core open-rewrite engine to the latest version. This has several effects on the way we use open-rewrite:

• due to the changed license of the rewrite-spring library, we can't just include an updated version of the rewrite-spring library that is compatible with the latest core engine.

• since the old apache licensed version of rewrite-spring is not compatible with the latest version of the core engine, we can't include the old version of rewrite-spring anymore going forward.

• this will require us to remove the automated spring version upgrade and refactor features from the OSS Spring Tools, including the UI to select/unselect individual recipes to be included in those upgrade tasks, the diff preview of the changes, etc. Basically, all the upgrade support will be gone moving forward. The validation of spring boot versions and support ranges will continue to work as is.

• we will document other ways users can use open-rewrite or other tools to assist them in upgrading existing projects to newer Spring versions.

• the features of the OSS Spring Tools that use open-rewrite under the hood for specific operations (e.g. a few quick fixes and code actions) will continue as is - and will be based on copies of the old recipes that we manually upgrade to work with the latest core engine of open-rewrite.