Small cleanup

[AbdullinAM]

Some small cleanups that are not entirely connected with each other rather that just being general refactorings and simplifications done while analyzing the code

• Extract more utility methods from KIAV to PsuUtils
• Simplify some of the TypeFormatter methods
• delegate TypeFormatter::formatFunctionType.parameterList formatting to dedicated method
• Use formatCommaSeparatedList in more cases where it can be used as a drop-in replacement. Other cases (e.g. visitFunctionLikeExpression) require more structural changes
• Extract a separate formatInitializerExpression method for formatting everything that comes after =

[hick209]

LTGM, assuming this is just house ordering, which is what it looked like to me, but since it's a big change I know I might have missed something.