DISPATCH-1803: prevent body_data sections from violating Q2 limit

[kgiusti]

This may be the wrong way to solve this - fixing it at the message construction phase rather than at message decode.

This patch adds a new body-data message API call:
void qd_message_body_data_append(qd_message_t *msg, qd_buffer_list_t *data);

A single call to this would replace this logic in the adaptors:

• //
• // Compose a DATA performative for this section of the stream
• //
• qd_composed_field_t *field = qd_compose(QD_PERFORMATIVE_BODY_DATA, 0);
• qd_compose_insert_binary_buffers(field, body);
• //
• // Extend the streaming message and free the composed field
• //
• qd_message_extend(msg, field);
• qd_compose_free(field);

[ChugR]

All adaptors should be required to use this interface.

[kgiusti]

Merged to dev-protocol-adaptors-2 branch