resourceloader: Refactor CSP $nonce passing

resourceloader: Refactor CSP $nonce passing

Follows-up 70941efd35562dcb700 which broke various public
signatures of the ClientHtml class that I'd prefer to handle
differently.

This commit mainly restores support for all previously public
signatures, and either removes the need for a parameter, or moves
it to the end of the original signature (as optional param).

* ClientHtml::getHeadHtml: Remove the positional/required parameter
  that was added. Restoring the method to being a stateless computer
  that requires no parameters. Pass the option via construct instead.

* ClientHtml::makeLoad:
  - Make $nonce optional.
  - Restore $extraQuery as optional.

* ResourceLoader::makeInlineScript: Document $nonce as optional
  (matching the implementation).

Change-Id: Iaf33f2a060048e6606fba8d875b6d2953b21ef45