soletta: update to 1_beta18

Idea here is that this one would be the Soletta version for Ostro V1. It would be nice to have mosquito PR merged and i2c-dev issue solved as well.

There's a new Soletta version with the following changes:

Changes on CoAP implementation improving memory-efficiency
Provide node types for a lot of OIC resources data models
Many changes on LWM2M API in order to have a more consistent API for all communication protocols
Added API to server side events on http-server with samples. It was supported on http-client as well.
Updated GPIO implementation for Zephyr considering changes on its API
Implemented sol-network and sol-socket for Zephyr
GPIO, AIO, PWM and UART bindings for Node.js
Added web inspector to sol-fbp-runner
Dependencies of samples were fixed
RIOT I/O implementation was updated to match API changes
Fix OIC to deal with cases where IPv4 isn't enabled

solettaproject / meta-soletta