Add ora_db_unique_name Terraform variable to set DB_UNIQUE_NAME

[GMafra]

Change Description:

Add terraform support for setting the Oracle database unique name (DB_UNIQUE_NAME).
Pass the new --ora-db-unique-name flag from terraform through to install-oracle.sh.

This brings the terraform layer to parity with install-oracle.sh, which already
supports --ora-db-unique-name for both Primary and Standby databases.

Solution Overview:

Implements ora_db_unique_name support on the toolkit terraform configuration

Optional variable; works for both Primary and Standby databases. When left empty the
existing ansible default applies (db_name for Primary, db_name_s for Standby)

Test Commands:

terraform init
terraform apply -var-file=terraform.tfvars

Test Prep:
The following variable can be provided to terraform (optional)

ora_db_unique_name = "ora19p"

An example value was added to the terraform.tfvars.*.example files

Test 1: details:

Terraform renders the install-oracle.sh command with --ora-db-unique-name when the
variable is set, and omits it when left empty.

The implementation should be transparent for other components of toolkit

Expected Results:

When ora_db_unique_name is set, the generated install-oracle.sh command includes
--ora-db-unique-name <value>, and the database comes up with the expected
DB_UNIQUE_NAME for both Primary and Standby installs.

oratk59-17 terraform test results

database values

[google-oss-prow]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: GMafra
Once this PR has been reviewed and has the lgtm label, please assign alexbasinov for approval. For more information see the Kubernetes Code Review Process.

The full list of commands accepted by this bot can be found here.

Details

Needs approval from an approver in each of these files:

• OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[mfielding]

Looks good; just on nit.