azure: support Hub/Spoke network architecture and add Fortinet deployment

[yeoldegrove]

Hub/Spoke Architecture

This adds support for Microsoft Azure's Hub/Spoke Architecture.
It does so by implementing a new variable network_topologywhich is set to plain(current setup) by default.
The new variable executes different terraform modules called network_{plain,hub,spoke} which implement the different network scenarios.
If network_topology="hub_spoke" is set, the new hub/spoke scenario is deployed.

A refernce to "Use Hub/Spoke network architecture" is in README.md and examples (to just uncomment) are in terraform.tfvars.

e.g.

plain network (default/current setup)

The plain network is still the default.

# no need to set this, as this is already the default.
network_topology = "plain" 

create hub + spoke network

To create both Hub/Spoke networks and a bastion host, set this in terraform.tfvars:

network_topology = "hub_spoke"                        # set network topology
vnet_hub_create = true                                # create hub vnet
bastion_enabled = true                                # deployment of bastion host
spoke_name = "sap-1"                                  # name for spoke to create

existing hub + create spoke network

To use an existing Hub network and bastion host and only deploy the Spoke network, set this in terraform.tfvars:

network_topology = "hub_spoke"                        # set network topology
vnet_hub_create = false                               # do not create hub vnet
vnet_hub_name = "myhubnet"                            # name of existing hub vnet
bastion_enabled = false                               # disable deployment of bastion host
bastion_host = "X.X.X.X"                              # public IP of existing bastion host in hub network
spoke_name = "sap-2"                                  # name for spoke to create

Fortinet Deployment

[arbulu89]

Many many comments.
I just checked the logic of the new code. I didn't check whether the terraform usage of the new components is correct or not, as it is pretty complex.

In any case, I miss some documentation in the terraform.tfvars.example file. This is the file most people use rather than the README file