Lwm2m standalone update

[joakimeriksson]

This is a significant update of the LWM2M engine so that it is more dynamic and more complete. Important changes:

• removed the flash consuming CoAP resources generated per registered LWM2M object and replaced with a more lightweight CoAP handler callback
• added more complete support for discovery (link format based)
• improved support for multi-read and multi write of both JSON and TLV
• created a set of easy to re-use IPSO object template for creating sensors and controllers (IPSO objects)
• supports create in a nicer way than the CoAP resource based implementation

[nfi]

👍