webapp should detect a geometry is a point when exporting to WCMP2

[maaikelimper]

As identified by BOM at Fiji training, when a user enters a point geometry in the dataset editor form, WCMP2 ES indexing fails. This is because the geometry is encoded as a polygon. The wis2box-webapp should encode WCMP2 geometry as a Point if minx=maxx and miny=maxy.

[maaikelimper]

Or:

• throw an error in minx=maxx and miny=maxy and refuse to continue
• automatically add -0.000001 and +0.000001 when values are the same ...

[tomkralidis]

Someone may really want to encode a point, so we should ensure both Point or Polygon (current/default) as supported.