Picotable: Add support for many-to-many fields
Picotable: Add support for many-to-many fields

Many-to-many field values will be passed to Column as Managers, so
detect if the value is a Manager and render its contents by
concatenating the values (of `value.all()`) with commas.

Refs SHOOP-975

jorge-marques/shoop,suutari/shoop,hrayr-artunyan/shuup,taedori81/shoop,suutari-ai/shoop,akx/shoop,jorge-marques/shoop,hrayr-artunyan/shuup,taedori81/shoop,suutari-ai/shoop,akx/shoop,taedori81/shoop,hrayr-artunyan/shuup,shawnadelic/shuup,shoopio/shoop,shawnadelic/shuup,shoopio/shoop,shoopio/shoop,shawnadelic/shuup,jorge-marques/shoop,akx/shoop,suutari-ai/shoop,suutari/shoop,suutari/shoop