Given some text and an item containing a Point geometry,
the `position` filter replaces occurences of @POS@ or
@POSITION@ with the item's geometry (it has to be lat/lon).
Occurrences of @DMS@ are replaced with the position in
sexagesimal degrees.
This can be used anywhere a Vue filter can. However, we
have used it in the event comments edit dialogue. The positions
are replaced before saving the comment to the database.
These are saved in the Vuex store and can be retrieved
via the `serverEvent` getter. There are also some
convenience getters for retrieving line status.
