The submodule 'SkyTools' was removed.
Instead, the NuGet packages SkyTools.Common and SkyTools.Patching
will be used.

Specifically, treating "Lifecycle Rebalance Revisited" the same as its predecessor "Citizen Lifecyle Rebalance", and "Ploppable RICO Revisited" the same as "Ploppable RICO".

The PackageReference items for the Roslynator NuGet package don't need
special settings, because everything is managed by the
Directory.Build.props file.

* Update the solution file to latest version
* Update SkyTools to version 1.12
* Update to the SDK style project format
* Fix code style (var and expression-bodied methods)
* Update the pull request CI action: replace NuGet GitHub Action; Run action for local pull requests only

Update pt.xml

Create XML localization files check action

Add GitHub build action for pull requests

improved Chinese Translation