404 page or some default route if the path doesn't match at all

[gashcrumb]

This is a...

[x] Feature request
[ ] Regression (a behavior that used to work and stopped working in a new release)
[ ] Bug report  
[ ] Documentation issue or request

Description

Occasionally I'll borrow the same window to look at the react UI when I've been looking at the angular UI by just changing the hostname in the URL (i.e. syndesis-staging -> syndesis-react-staging etc). But given that we've some similar and some different routing across the two apps, usually the route I'm giving the react app is totally wrong, and I wind up with a blank window. We should either:

• show a 404 page
• redirect to the dashboard

I lean towards the former only because it's handy to be able to see the URL that leads you to a 404 sometimes.

[riccardo-forina]

We have a top level 404 page, but we need to add one basically everywhere we have a non exact Route