Add strict http mode for additional validation

[JoshCap20]

This would solve balance between current validation and developer freedom. Would be helpful for debugging when behavior is unintentional.

Strict HTTP Mode would be enabled on the AreionServerBuilder and enforce additional http-specific validation:

• Proper response types for HTTP methods (e.g. head has no response body)
• Only allow HTTP methods (currently included in current validation)
• tba