The various XDOM manipulation APIs can produce stack overflow exceptions in case of deep hierarchy

All the APIs which navigate the XDOM (Block#traverse, MacroTransformation#prepare, Block#getFirstBlock, Block#getBlocks, BlockNavigator, etc...) and using recursion to navigate children which will end up in a StackOverflowException if the hiearchy is deep enough or the stack small enough.

BlockNavigator should be improved to not be impacted anymore and cover more use cases (like just consuming a XDOM instead of returning a list of blocks).