Support adding to the pages to be visited in build time render during build time render

**Enhancement**
With blocks, it's now possible to discover content at build time rendering (ie reading a number of markdown files in a directory), this might mean that we want to then visit routes to get output from too. This is not currently possible due to the build time render paths being static in the dojorc. It'd be nice if it would be possible to dynamically add to those paths when running in build time rendering