docs: Correct URL of Nominatim's wikipage
docs: Remove docs generation for ipclient
Remove geocode-glib module from docs

There is no public API in that module and due to gtk-doc not generating
an xml from for that, build breaks:

../geocode-glib-docs.xml:20: element include: XInclude error : could not
load ../xml/geocode-glib.xml, and no fallback was found
Release 0.99.2