Make class static (https://josefpihrt.github.io/docs/roslynator/analyzers/RCS1102)

Process completed with exit code 1.

Converting null literal or possible null value to non-nullable type.

Possible null reference argument for parameter 'node' in 'void UcLoggersTree.SetLogLevel(TreeNode node, LogLevel level)'.

Make class static (https://josefpihrt.github.io/docs/roslynator/analyzers/RCS1102)