Determine best way to version API enpoints

[zmon]

When the backend changes it's API we need an easy way to have different versions of the front end to use the correct version of the API.

For example pagination to the Applicant, the grid is being changed to pass back pagination information as well as data. The current version is only passing back data.

[mattsplat]

The approach I am seeing done is essentially having a separate set of routes and controllers for each version on the backend. For the frontend we can just keep the version on separate branches.