put 'enum class Type' into ScServiceProvider

The mapping of historic stardiv.* service names relied on
correct order in array aOldNames and fixed numbers for service
types via #define.
This mapping is now done the same way as for the other service names.
Nice side-effect, we don't need to assign numbers any more.

getFieldType moved up in one namespace with the other stuff
for ScServiceProvider.

Change-Id: I932d1d1475563db82061ec7b5913f2361a6f4362
Reviewed-on: https://gerrit.libreoffice.org/23365Reviewed-by: Noel Grandin <noelgrandin@gmail.com>
Tested-by: Noel Grandin <noelgrandin@gmail.com>