Allow overriding SSL configuration

[rhysparry]

Background

In Octopus Server we want to be able to control the supported protocols used by SSL. Currently Halibut enables TLS 1.0-1.3 to maximise compatibility. We would like to defer this configuration to the underlying Operating System where possible.

By allowing the SSL configuration to be overridden, we can transition between these two states in a controlled manner.

Results

• Changes default SSL protocols to be defined by the underlying Operating System
• Allows overriding defined set of supported protocols. Two implementations include:
  • DefaultSslConfigurationProvider uses the underlying Operating System defaults.
  • LegacySslConfigurationProvider explicitly allows TLS 1.0-1.3, mirroring previous behaviour.

Before

• TLS1.0-1.3 would be considered supported protocols. Underlying Operating System settings may explicitly make some of these options unavailable.

After

• The default sbet of supported protocols is defined by the underlying Operating System
• The set of protocols can be overridden if desired

How to review this PR

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Pre-requisites

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• I have considered appropriate testing for my change.