per chat, rizen/haarg/pd/preaction

the headblock field for templates wil be removed, and the extraheadtags field will be subclassed so that it will process meta data / content profiling type variables, just as just like the head block does now. THis is done because the extraheadtags field is a standard field for all assets.

It would be nice, during the upgrade, to append existing contents from head block to "extra headers" so nothign is lost. I think that was part of the plan.