Inconsistent API for operation level write concern

Some operations, like Insert_one, allow write_concern in an options object. Others, like find_one_and_delete, do not and only take the value from the collection level default.

This may have been due to mongoc limitations, but with the addition of the xxx_xxx_with_opts functions, we have more API choices now.

For consistency, we should add write_concern to all write operation options classes.