feat(rds_instance_transport_encrypted): add new check

[MrCloudSec]

Description

Add new check called rds_instance_transport_encrypted

License

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

[MrCloudSec]

Thanks to @Fennerr for the idea!

[Fennerr]

Just moving across the info from the slack chat I had with Sergio to here:

For Oracle databases the rds client also needs to retrieve the option groups, and then check for the SQLNET.SSL_VERSION option to that group. https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Appendix.Oracle.Options.SSL.html#Appendix.Oracle.Options.SSL.OptionGroup
The following values are allowed for this option setting:

"1.0" - Clients can connect to the DB instance using TLS 1.0 only.
"1.2" - Clients can connect to the DB instance using TLS 1.2 only.
"1.2 or 1.0" - Clients can connect to the DB instance using either TLS 1.2 or 1.0.

The check can also check if it is set to use TLS 1.0

For existing Oracle SSL options, SQLNET.SSL_VERSION is set to "1.0" automatically. You can change the setting, if necessary.

I can add this to the current check, or it can be a separate check

[MrCloudSec]

Just moving across the info from the slack chat I had with Sergio to here:

For Oracle databases the rds client also needs to retrieve the option groups, and then check for the SQLNET.SSL_VERSION option to that group. https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Appendix.Oracle.Options.SSL.html#Appendix.Oracle.Options.SSL.OptionGroup The following values are allowed for this option setting:

"1.0" - Clients can connect to the DB instance using TLS 1.0 only.
"1.2" - Clients can connect to the DB instance using TLS 1.2 only.
"1.2 or 1.0" - Clients can connect to the DB instance using either TLS 1.2 or 1.0.

The check can also check if it is set to use TLS 1.0

For existing Oracle SSL options, SQLNET.SSL_VERSION is set to "1.0" automatically. You can change the setting, if necessary.

I can add this to the current check, or it can be a separate check

@Fennerr, this is a great idea, it would be awesome if you can do it, we have include it in our roadmap anyway.
If you finally do it, please create a new PR as we want to include this check in the next release that we are going to do tomorrow. Thanks!