Add support for aws eu-south-1 region

[joshuastern]

Description

Add support for creating AWS Route53 Alias records in the eu-south-1 region

Fixes #ISSUE

Checklist

• Unit tests updated
• End user documentation updated

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[joshuastern]

I signed it

[Raffo]

I verified this with https://docs.aws.amazon.com/general/latest/gr/elb.html

[Raffo]

/lgtm
/approve

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[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: joshuastern, Raffo

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