Add API to save/load array from disk

[9prady9]

Description

Add API to wrap the following C API

• af_save_array
• af_read_array_index
• af_read_array_key
• af_read_array_key_check
• af_array_to_string

[9prady9]

I am still contemplating if this would any benefit to the wrapper in general given that serialization and de-serialization are already supported. Hence, the timeless milestone.