Add ConfigureAspNetCoreDefaults

[HaoK]

Initial prototype of #117

• New ConfigureAspNetCoreDefaults() that will add all of the IConfigureOptions for the default sections
• Currently: Kestral/OIDC/Google/Facebook/Twitter/MSA/JwtBearer/Identity
• Moved kestrel config under Microsoft:AspNetCore:Hosting

[dnfclas]

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[Eilon]

cc @davidfowl @DamianEdwards

We need to think a bit more about which dependencies go where. We can't add too many deps to the mini-metapackage. But, if we add this to the All-metapackage, then it can't be used from .NET Framework apps/templates.

[HaoK]

Updated using new options infrastructure. Should the kestrel setup move to Kestrel instead of living here like the rest of the default setup?

[HaoK]

@JunTaoLuo do you own MetaPackage? Who should review this change?

[HaoK]

Merged without the kestrel changes which would break templates without the corresponding config update