Additional changes:
* align vpc-connector interface to Cloud Functions
* split managed and unmanaged resources into separate files, this makes
easier to introduce further changes
* add support for contexts
* move `vpc_connector` variable to variables.tf for Cloud Functions
* remove `create` from `vpc_connector` in Cloud Functions as it was
sharing the meaning with `vpc_connector_create`
* fix: allow configuring `docker_repository` for cloud-function2
When docker repository is not specified by default docker repository
`projects/PROJECT_ID/locations/REGION/repositories/gcf-artifacts` is used.
In such a case, terraform plan always generates a difference for `docker_repository`
field as the module passes null value but the tfstate file has the above specified
default value. This fix allows one to prevent unnecessary infrastructure change when
using the default repository as well as any user created repository.
* doc: updated README for cloud-function-v2
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Co-authored-by: Ludovico Magnocavallo <ludomagno@google.com>
