Updates to operation mode, SGs, cluster type, and additional flags.

[JDBraun]

This PR addresses the following issues:

• 56: The egress rules for the PrivateLink endpoints have been removed.

• 55: The VPC endpoints now have been updated to use the PrivateLink endpoint

• 53: The cluster example has been updated to explicitly call out the User Isolation Mode in the data security mode. This can be updated based on user configuration, information here.

• 52: The README and the associated variables have been updated to reflect 'Sandbox' instead of 'Standard'.

• 51: 8443-8451 have been updated to be added to PrivateLink endpoints.

New Additions:

• A compliance_security_profile flag has been added. If this is set to true, it adds an egress 2443 rule to the data plane security group and an inbound 2443 rule on the PrivateLink endpoint. Since this is only relevant for ESC. 2443 has subsequently been removed from the list of ports in the example.
• A enable_admin_configs has been added. Unfortunately, due to the evolving nature of this API, it has caused issues in certain provider versions. So, this has been defaulted to false. Examples admin configurations, that follow our best practices, have been added in the resource with their documentation, a user should evaluate if they would like to enable this or not.

[JDBraun]

@metrocavich - mind taking a look on the nitro update?

[metrocavich]

All looks good to me now. (And I really looked for something else to comment on...)

[JDBraun]

@db-wenxin + @ryan-gord-db - check out the changes to the SG rules in network.tf I added dynamic rules in the existing block now