ContentSecurityPolicy builders should be discardable results

[0xTim]

Since ContentSecurityPolicy is a class and the various functions affect the store policies, they should all be marked with @discardableResult. This allows you to do things like:

let csp = ContentSecurityPolicy = ContentSecurityPolicy().defaultSrc("self")

if env == .production {
  csp.blockAllMixedContent()
}

This currently works but produces a warning since you aren't using the result of blockAllMixedContent.