Member pvParam in attribute directory: consider removal

Optimization 1) For reducing the memory footprint: Consider to remove member pvPram of the attribute directory type. Instead, pass pvParam as parameter to CipObj_* functions directly. This would save several hundred bytes of RAM, since this multiplies by the number of attributes in the system.

Optimization 2) For reducing the memory footprint: Consider to remove members pfValidate and pfUpdate of the attribute directory type. Instead, move them into the object entry type which exists one per object and dispatch validation and update calls internally by attribute. This would save several hundred bytes of RAM, since this multiplies by the number of attributes in the system.