[DOC, BUG?] Example for Preset Location of Dipole Forward Model

[alexrockhill]

This is a PR for an example using the position and orientation coordinates of the preset dipoles in scanner RAS (mm) and using it as input for a forward model which then is able to give the modeled evoked topography for mag, grad and eeg sensors.

There is a bit of an issue where the position using plot_dipole_locations and the evoked potentials are correct but the orientation does not match binder. The first preset is shown in the screenshots below. I'm not sure, but orientation (1, 1, 1) is the first preset and in RAS that would seem to me to me that the arrow should be pointing right, anterior and superior, which it does in the example from this PR but it is not that orientation in the binder.

[hoechenberger]

Thanks for reporting! I'll have a look.