Update methods for Seshat page navigation on world map

[edwardchalstrey1]

• Closes ✨ [Feature request] - <Hovering over polities in maps> #219 by making the most recently hovered over polity show up in the top left
• Adds links to the legend

[edwardchalstrey1]

@MajidBenam Could you take a look at this suggestion which I have added to the world map? I have put seshatdata.com onto this new branch.

Actually I think I have may have got your suggestion the opposite way around, but maybe compare the hover functionality now with seshat-db.com and see what you think. The difference is basically that you now don't need to click a polity for it to remain in the top left after hover - but this actually makes it if anything harder to reach the box without accidentally hovering over another polity, so I could remove that change.

The other new change is that I have added the Seshat page links directly in the legend as well, which gives you another way to reach Seshat pages. But also don't forget the fastest way to get there is to double click a polity shape.

Let me know your thoughts :)

[MajidBenam]

I like the new style and the fact that you can also go to pages from the selection box. I think that will do the job. I did not know, that double clicking takes us to the page as well. I think it is good now. I will make sure that the changes are reflected on seshat-db.com as well.

[edwardchalstrey1]

I like the new style and the fact that you can also go to pages from the selection box. I think that will do the job. I did not know, that double clicking takes us to the page as well. I think it is good now. I will make sure that the changes are reflected on seshat-db.com as well.

@MajidBenam thanks - on a later commit in this PR that is now merged (but wasn't on seshatdata.com) I restored the previous way of handling the "mouseout", as per my comment above, so when you update seshat-db it will behave as before, which for the reason I explained above I think is the best. Can easily modify this behaviour later if we like