Add support for automatic registering of RequestLocalizationOptions

[Carl-Hugo]

Add support for automatic registering of RequestLocalizationOptions.

• RequestLocalizationOptions should be added to the IServiceCollection automatically.
• SupportedCultures and SupportedUICultures should be automatically populated by default values (all translations).
• DefaultRequestCulture should be defaulted to new RequestCulture(culture: "en", uiCulture: "en").
• SupportedCultures, SupportedUICultures and DefaultRequestCulture should be parametrable.
• Users should be able to opt-out of this with a simple bool like EnableConfigureRequestLocalizationOptions = false.

[Carl-Hugo]

After revisiting the specs during the implementation:

• Having RequestLocalizationOptions registered was not useful since all options has been centralized under ForEvolveLocalizationOptions.
• ForEvolveLocalizationOptions is registered as a singleton and obtainable using DI.
• The supported cultures are hard coded (for now) in the ForEvolveLocalizationStartupExtensions.AddForEvolveLocalization(...) method.
  • Resource files need to be added manually to the project anyway (for now at least).
  • The default culture is also hard coded there.
• The "opt-out" is not needed anymore and has been replaced by the ability for a user to configure the RequestLocalizationOptions when calling services.AddForEvolveLocalization(...).
  • The option is under ForEvolveLocalizationOptions.RequestLocalizationOptions.
  • The registration will be done under Create IApplicationBuilderextensions methods #7