increase localStorage page history variety

we already summarise lead keyword and section totals for the last 100 articles.

this is to add lead author, blog and series, as well as all the display names

The aim is so later we can use the info to show a "Jump-to" bar on the front based on what users like.

/cc @stephanfowler I'd love some feedback since it's your area of expertise =)
what are you trying to achieve here? it is weird - calling a function which is setting things on `page`(?), creating an instance of that and setting it to the `meta` key