Add pgcrypto to aws-broker RDS instances

[cweibel]

Changes proposed in this pull request:

• Add pipeline tasks for dev/stage/prod to run "init-db" which applies database extensions and other configuration to the user databases on the corresponding RDS instances.
• The scripting is very similar to what was done in terraform-provision with Add pgcrypto to defect dojo and domains_broker RDS instances terraform-provision#1910 (defect dojo & domains_broker) and Add pgcrypto to concourse credhub staging db terraform-provision#1901 ... 1906 for concourses, credhubs and autoscalers. The scripting previously already existing for CCDB, BOSH & OpsUAA.
• Tested in dev by manually overriding the pipeline.
• Part of https://github.com/cloud-gov/private/issues/2408

Security considerations

Needed for CIS Benchmark requirements for pgcypto in Nessus scans

[markdboyd]

Do we need any of this here? I'm very confused by references to Shibboleth here

[cweibel]

I was trying to keep the script that runs in terraform-provision as close to this as possible to make future upgrades to the base script easier to roll out.

[markdboyd]

If we want to reuse the script, should we put it in cg-scripts and reference it in the pipelines?

It's a little confusing to have these references in this repo script when they're not related to the aws-broker at all

[cweibel]

I've removed the if block to keep the script to only be focused on the RDS instances for aws-broker.

[markdboyd]

I'm assuming none of this is relevant here

[cweibel]

The goal was to keep this and https://github.com/cloud-gov/terraform-provision/blob/main/ci/scripts/create-and-update-db.sh as close as possible, the only difference now are lines 9&10.

I can pull the entire if block if that is desired, it is, strictly speaking, not required for this RDS instance