edits to network.tf

[claudia-lola]

Vars within network.tf are now able to be defined two different ways.
Example:
tenant_id used to require
tenant_id = module.<module-name>.project["<project_name>"].id
For the id of a project to be created by the tofu module to be used for the var or the known id if the project already exists.
Now can use that or
project = "<project_name>" and tofu will check the id for that project or can use known id for project as a string.

The same has been done for network_id with network var
subnet_id with subnet var
and router_id with router var.

This allows flexibility in defining these vars.

Downside: if project and tenant_id are both defined, the project value will override the tenant_id value.
Same goes for:
network overrides network_id
subnet overrides subnet_id
router override router_id
-> Can be swapped but one will always override the other with current ( condition ? true do A : false do B ) set up.