Address Fortigate hub-env remaining issues - mgmt-vpc public access needs 0.0.0.0/0 (IGW or NAT) and hardcoded ha password...

context
- #446
- #258

see https://github.com/GoogleCloudPlatform/pubsec-declarative-toolkit/blob/main/solutions/project/hub-env/fortigates.md#known-issues

GCP SDN connector not working. The connection is initiated from the fortigate mgmt interface. It requires access to the Google API public endpoint. The mgmt VPC has no route to the internet in order to meet security controls.
One option could be to :
- create a PSC targeting "all-apis" on the internal VPC
- create a dns zone for googleapis.com with a wildcard record that forwards the traffic to the PSC
- establish VPC peering between mgmt and internal VPC
- add a route for 0.0.0.0/0 on the mgmt VPC
- create firewall rule allowing access from fortigate SA to PSC

## fix
we will be adding a route to 0.0.0.0/0 and enable a egress firewall rule on the mgmt VPC as well as an Internet Gateway instead of a NAT - making the management VPC public for now - due to demo time constraints

the following parameters are currently embedded into the fortigate config (GCE metadata). it would be great if they could be customized with setters.
- fortigate timezone
- fortigate ha pw

## fix
- we will be adding a kpt-set settings.yaml entry for the pw