Add TraversalMode (always NORMAL for now)
DRY out & isolate (with mocks) PageTraverserTest
Add CustomSubmitter (not yet used in prod code)
Make TraversalModes NORMAL or SUBMIT
Make PageTraverser honour TraversalMode
Create PageTraversals in Route via factory
Rename appendTraversalByMethodToPageDescriptor to appendTraversal
Make appended untraversed methods have SUBMIT mode
Use route runner's journal in LabelledXssGenerator
Add CustomSubmitter to int test login page
Fix submit method appending:
 - Don't count NORMAL mode traversals when finding untraversed submit methods
 - Ensure unused submit methods on non-leaf nodes result in creating new route