expose tables as public instead of private

[DenisCarriere]

External contracts cannot implement with this interface if the table structures are private.

atomicassets::templates_t _templates( "atomicassets"_n, collection_name.value );
auto itr = _templates.find( template_id );

❌ ERROR message receive at compile:

error: 'templates_t' is a private member of 'atomicassets'
    atomicassets::templates_t _templates( "atomicassets"_n, collection_name.value );

[teeg74]

??