Always use system TLS defaults

[rhysparry]

Background

While we were rolling out the change to adapt Halibut configuration to use system defaults we provided a mechanism for consumers of Halibut (i.e. Tentacle and Octopus) to override these defaults if necessary.

Now that we have confirmed that switching to system defaults has not caused issues, and has improved security (by allowing older TLS protocols to be disabled by the Operating System) we are removing the ability to configure these protocols directly.

Results

• Removes the ISslConfigurationProvider and its provided implementations
• Exposes the SslProtocols value used internally via SslConfiguration.SupportedProtocols. This value has been set to None, which "Allows the operating system to choose the best protocol to use, and to block protocols that are not secure." (see docs)
• Updates usages of the ISslConfigurationProvider to access this static property.
• Removes the ability to supply SSL configuration within the HalibutRuntimeBuilder
• Resolves EFT-157

Before

• TLS Protocols supported by Halibut could be overridden by the application.

After

• TLS Protocols supported by Halibut are configured at the Operating System level.

How to review this PR

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