add new resource OptionGroup

[kprahulraj]

Issue #2065

Description of changes:

The Amazon RDS OptionGroup resource represents the RDS Aurora Serverless API's command-line/configuration options for DB clusters.

• generator config file to un-ignore OptionGroup resource
• generate RDS service controller with support for the OptionGroup resource
• e2e python test for CRUD operations for a OptionGroup

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[ack-prow]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: kprahulraj
Once this PR has been reviewed and has the lgtm label, please assign jlbutler for approval by writing /assign @jlbutler in a comment. For more information see the Kubernetes Code Review Process.

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

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

[kprahulraj]

/retest

[ack-prow]

@kprahulraj: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
rds-verify-code-gen	0d2c010	link	false	/test rds-verify-code-gen

Full PR test history. Your PR dashboard.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository. I understand the commands that are listed here.