Enable Security Headers for Orchard Core Website

[hishamco]

Related to OrchardCMS/OrchardCore#13896

@agriffard can we enable the security headers to get a better result in the security check?

[Piedone]

I'd rather use our security defaults which is basically a one-liner for all of these settings, tailored for the app's features.

[hishamco]

The important thing is to move up the rank from "F" :)