Integrate with Dexterity Type Editor

Register the field to be listed by `plone.schemaeditor`, i.e. in `dexterity-types/*/@@add-field`.

Start by locating the registration used by plone.schemaeditor at dexterity-types/*/@@add-field and inspect how available fields are listed. The work is done when this geolocation field appears in the Dexterity Type Editor's add-field list; verify the result through the editor if the project provides a test or runnable Plone instance.

Written by the indexing model from the issue text.