CloudSQL PSC Endpoints support

[wiktorn]

Add PSC Endpoints to net-address. Simplifies creation of the PSC endpoint for any PSC supporting resource.

Additional changes:

• Added message how to generate inventories for YAML based tests.
• Added E2E tests for CloudSQL

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Checklist

I applicable, I acknowledge that I have:

• Read the contributing guide
• Ran terraform fmt on all modified files
• Regenerated the relevant README.md files using tools/tfdoc.py
• Made sure all relevant tests pass

[juliocc]

decide what to do with network_config.connectivity.psc_allowed_consumer_projects (either remove or merge var.psc_consumers into var.network_config.connectivity)

I'm not so sure I like having the creation of the PSC endpoints in this module. Are we going to add PSC endpoint management to every product that supports it (e.g. GKE, Apigee, etc)?

Personally I'd prefer keeping this module just setting the allowed PSC consumer projects and leaving the creation of the endpoints to the consumer. Having said that, PSC creation is becoming common enough that I can see the use of a net-psc-endpoint module that creates the google_compute_address and the google_compute_forwarding_rule.

[ludoo]

I'm not so sure I like having the creation of the PSC endpoints in this module. Are we going to add PSC endpoint management to every product that supports it (e.g. GKE, Apigee, etc)?

Personally I'd prefer keeping this module just setting the allowed PSC consumer projects and leaving the creation of the endpoints to the consumer. Having said that, PSC creation is becoming common enough that I can see the use of a net-psc-endpoint module that creates the google_compute_address and the google_compute_forwarding_rule.

100% agree, endpoints are conceptually part of the net- family of modules, as they materialize an LB and consume an address. I would explore either integration into net-address or a new net-xxxx module for them.

Plus, this would avoid integrating them everywhere as more more products start offering support, like Julio noted above.

[wiktorn]

Personally I'd prefer keeping this module just setting the allowed PSC consumer projects and leaving the creation of the endpoints to the consumer. Having said that, PSC creation is becoming common enough that I can see the use of a net-psc-endpoint module that creates the google_compute_address and the google_compute_forwarding_rule.

100% agree, endpoints are conceptually part of the net- family of modules, as they materialize an LB and consume an address. I would explore either integration into net-address or a new net-xxxx module for them.

Plus, this would avoid integrating them everywhere as more more products start offering support, like Julio noted above.

I really liked the idea of adding that to net-address, which already has some PSC logic, so I followed this path.

This PR is now a bit split-brained, between E2E tests in cloudsql-instance and changes in net-address, but I hope that you don't mind that.

[ludoo]

two nits, great PR