Make Person and Board Term types group content

To make figuring out permissions so that clerks in the same city
can edit each other's content, make the Board Term and Person
content types group content by giving them a field with machine
name ``og_group_ref`` and label City that references a City group.

Update type-level and field-level permissions for the types. These
may need a little refinement and testing.

Addresses #3484
Automatically set city

Implement ``hook_node_presave`` to automatically set the city for
a person, board and board term from the user or board.

Addresses #3484