Use Route53 resolver endpoint security group AWS best practices, or allow BYO security group for the outbound endpoints

[veqryn]

Currently, the Route53 module uses the "default" security group.
Many companies have locked down the default security group. In our AWS environment, we have deleted all the inbound and outbound rules on the default security group (intentionally, to force each application to use a security group specific to it).

Additionally, the default security group does not follow AWS Best Practices for Route53 Outbound Endpoints.
https://docs.aws.amazon.com/Route53/latest/DeveloperGuide/best-practices-resolver-endpoint-scaling.html

This PR stops using the default security group, and creates a security group that follows the aws best practices.
It also allows a bring your own security group for the endpoint.
Existing formats were followed.

[veqryn]

Hi @jmolnar-zscaler , can I ask why this one was closed? We require it for zpa to work in our environment.

[jmolnar-zscaler]

apologies for lack of response. I took these commit proposals and are running them through validation for our next release as well. #101

[veqryn]

Thank you!