index pleiades ids and lat/long info

[emylonas]

we are adding an @ref`` attribute onwhich contains the URL to a Pleiades ID. Also, inside settlement, there is alat,lon` element. (lat,lon) are decimal numbers separated by a comma. We should probably index them, especially Pleiades IDs so that they can be accessed from the API - it's going to link us up with other places in the Ancient world gazetteer and related applications.

[emylonas]

Checking up on this - The lat/lon appear not only in the list of places on the search page but also in the inscription display. We should clean up that location information display once and for all - perhaps chat at some point on Monday?

[emylonas]

done