add cloud identity data sources

[megan07]

Fixes hashicorp/terraform-provider-google#6704

Release Note Template for Downstream PRs (will be copied)

`google_cloud_identity_groups`

`google_cloud_identity_group_memberships`

[modular-magician]

Hi! I'm the modular magician. Your PR generated some diffs in downstreams - here they are.

Diff report:

Terraform GA: Diff ( 8 files changed, 177 insertions(+))
Terraform Beta: Diff ( 9 files changed, 402 insertions(+))
TF Conversion: Diff ( 1 file changed, 13 insertions(+))

[modular-magician]

I have triggered VCR tests based on this PR's diffs. See the results here: "https://ci-oss.hashicorp.engineering/viewQueued.html?itemId=123210"

[modular-magician]

Hi! I'm the modular magician. Your PR generated some diffs in downstreams - here they are.

Diff report:

Terraform GA: Diff ( 7 files changed, 164 insertions(+))
Terraform Beta: Diff ( 9 files changed, 402 insertions(+))

[modular-magician]

I have triggered VCR tests based on this PR's diffs. See the results here: "https://ci-oss.hashicorp.engineering/viewQueued.html?itemId=123212"

[modular-magician]

I have triggered VCR tests in RECORDING mode for the following tests that failed during VCR: TestAccFolderIamAuditConfig_multiple You can view the result here: "https://ci-oss.hashicorp.engineering/viewQueued.html?itemId=123214"

[danawillow]

Would you mind requesting someone else for the review? I've got some other things on my plate that I'd like to get done today.

[c2thorn]

LGTM!