Use Percona XtraDB Cluster 8.0 by default

[ctlong]

What is this issue about?

CF-D currently self-selects Percona XtraDB Cluster 5.7 by default. However, 5.7 is out of support, and we should be using 8.0.

We should promote operations/experimental/use-mysql-version-8.0.yml to the base manifest.

Updates from 5.7 to 8.0 are supported by the pxc release. We should consider making this a major release though, to encourage operators to back up their databases beforehand.

What version of cf-deployment are you using?

v33.10.0

Please include the bosh deploy... command, including all the operations files (plus any experimental operation files you're using):

N/A

Please provide output that helps describe the issue:

N/A

What IaaS is this issue occurring on?

All

Is there anything else unique or special about your setup?

None

Tag your pair, your PM, and/or team!

None

[jochenehret]

Released in v34.0.0: https://github.com/cloudfoundry/cf-deployment/releases/tag/v34.0.0