Add Cloud SCC Notification Config resource

[modular-magician]

Fixes hashicorp/terraform-provider-google#7995

`google_scc_notification_config`

Note: I tried to run the generated ACC test, but I ran on this error:

terraform-provider-google % make testacc TEST=./google TESTARGS='-run=TestAccSecurityCenterNotificationConfig_sccNotificationConfigBasicExample'
==> Checking source code against gofmt...
==> Checking that code complies with gofmt requirements...
go generate  ./...
TF_ACC=1 TF_SCHEMA_PANIC_ON_ERROR=1 go test ./google -v -run=TestAccSecurityCenterNotificationConfig_sccNotificationConfigBasicExample -timeout 240m -ldflags="-X=github.com/hashicorp/terraform-provider-google/version.ProviderVersion=acc"
=== RUN   TestAccSecurityCenterNotificationConfig_sccNotificationConfigBasicExample
=== PAUSE TestAccSecurityCenterNotificationConfig_sccNotificationConfigBasicExample
=== CONT  TestAccSecurityCenterNotificationConfig_sccNotificationConfigBasicExample
cannot run Terraform provider tests: unexpected error: openpgp: signature made by unknown entity
FAIL	github.com/hashicorp/terraform-provider-google/google	0.407s
FAIL
make: *** [testacc] Error 1

I have no idea how to solve this error, so I'm open to suggestions :).

If this PR is for Terraform, I acknowledge that I have:

• Searched through the issue tracker for an open issue that this either resolves or contributes to, commented on it to claim it, and written "fixes {url}" or "part of {url}" in this PR description. If there were no relevant open issues, I opened one and commented that I would like to work on it (not necessary for very small changes).
• Generated Terraform, and ran make test and make lint to ensure it passes unit and linter tests.
• Ensured that all new fields I added that can be set by a user appear in at least one example (for generated resources) or third_party test (for handwritten resources or update tests).
• Ran relevant acceptance tests (If the acceptance tests do not yet pass or you are unable to run them, please let your reviewer know).
• Read the Release Notes Guide before writing my release note below.

Derived from GoogleCloudPlatform/magic-modules#4938