feat: Enable the creation of private NAT gateways

[laserpedro]

fixes #1060

Description

Enable the setup of private NAT Gateways by exposing the native resource argument connectivity_type and the related arguments.

Motivation and Context

If the module is used in the context of corporate network setup, a private nat gateway can be required since we are not created and internet gateway in the vpc.

How Has This Been Tested?

• I have updated at least one of the examples/* to demonstrate and validate my change(s)
• I have tested and validated these changes using one or more of the provided examples/* projects

• I have executed pre-commit run -a on my pull request

[bryantbiggs]

how has this been tested? does this example deploy without issue?

[laserpedro]

Hello @bryantbiggs ! Did you have the time to have a look at my PR ? Thank you !

[andre-lx]

Hi @laserpedro

Nice job.

Just one question, I was checking and the support for private nat gw is something I am looking forward in the module, unfortunately this does not take in account some scenarios where you can have public nat gw on your public subnets and private nat gw on you private subnets right?

Thanks

[laserpedro]

Hi @andre-lx ,

Thank you for your comment, much appreciated.
So in this fully private NAT Gateway configuration, we would not create an IGW so you could not have a mix of public and private nat.
If I am correct, you would like to have some nat created in subnets with a route to the igw (the public ones) and others created in the subnets in subnet with a route with the tgw (the private ones) ?