Adding new and improved contribution guidelines
Adding new and improved contribution guidelines

Signed-off-by: James Sutton <fad1c6fab36ea85fbb0be247536a568f370443c8@uk.ibm.com>

eclipse/paho.mqtt.embedded-c,eclipse/paho.mqtt.embedded-c,monstrenyatko/ArduinoMqtt,eclipse/paho.mqtt.embedded-c,monstrenyatko/ArduinoMqtt,eclipse/paho.mqtt.embedded-c,eclipse/paho.mqtt.embedded-c