Introduce office POI class

[phanecak-maptiler]

This re-implements following OpenMapTiles pull-request into planetiler-openmaptiles:

• Introduce office POI class openmaptiles/openmaptiles#1423

[phanecak-maptiler]

Btw, review skipped here, since review in progress in openmaptiles#126 where this was merged.

[wmisener]

Hi, I think this PR has broken universities (amenity=university in OSM) in OMT, they all appear in the tiles as class=office + subclass=university instead of class=college + subclass=university, which they used to. I think this happened because university can be a value of both amenity=* and office=* in OSM? I'm not super-familiar with how this code works though, but I assume this was unintentional?

[phanecak-maptiler]

Hi, I think this PR has broken universities (amenity=university in OSM) in OMT, ...

Oh, thanks. Noted here: #31 since this PR is closed.