Adding support for route tables and their child resource, routes

[thinkdavid]

This PR closes #

The changes in this PR are as follows:

• Adding support for route tables
• Adding support for routes

I have read the contributing guidelines and have completed the following:

• [x ] Tested my code end-to-end against a live Azure subscription.
• [x ] Updated the documentation in the docs folder for the affected changes.
• [ x] Written unit tests against the modified code that I have made.
• [ x] Updated the release notes with a new entry for this PR.
• [x ] Checked the coding standards outlined in the contributions guide and ensured my code adheres to them.

If I haven't completed any of the tasks above, I include the reasons why here:

Below is a minimal example configuration that includes the new features, which can be used to deploy to Azure:

let deployment =
                    arm {
                        location Location.EastUS
                        add_resources
                            [
                                routeTable {
                                    name "myroutetable"
                                    add_routes [
                                        route {
                                            name "myroute"
                                            addressPrefix "10.10.90.0/24"
                                            nextHopType Route.HopType.VirtualAppliance
                                            nextHopIpAddress "10.10.67.5"
                                        }
                                        route {
                                            name "myroute2"
                                            addressPrefix "10.10.80.0/24"
                                        }
                                    ]
                                }
                            ]
                    }

[ninjarobot]

Thanks for the contribution! My only suggestion is to encode the requirement for the nextHopIpAddress in the HopType DU so this can be enforced in the route builder and prevent user error.

[ninjarobot]

Thanks for the contribution, this is included in the 1.7.8 release and now available on nuget!