Review SSL info contribution and its use of management.health.ssl.certificate-validity-warning-threshold

[wilkinsona]

Having a management.health.ssl property affect SSL info doesn't feel quite right, particularly as it's management.info.ssl.enabled that's used to enable/disable the SSL info contribution. Having separate threshold properties for SSL health and SSL info also doesn't feel quite right either as I expect that you'd always want them to have the same value.

[philwebb]

We discussed this today and we think we should probably get rid of the feature in info.