different approach to client library compatibility for no decoration

[davidnuescheler]

i looked at the client compatibility layer and i am wondering

(a) if it works in prod as it operates on internal hlx data attributes
(b) if it is too complicated
(c) should we include it directly in the head.html for projects that have not changed the head.html

[davidnuescheler]

this is in reference to #416

[davidnuescheler]

b6ae1cb

@rofe, WDYT? i am actually thinking a mix of the two solutions could be a good approach where we have a separate .js that could be included in head.html easily.