[v3.x] add IqrfDb examples

• iqrfDb_Enumerate
• iqrfDb_GetBinaryOutputs
• iqrfDb_GetDevice
• iqrfDb_GetDevices
• iqrfDb_GetNetworkTopology
• iqrfDb_GetLights
• iqrfDb_GetSensors
• iqrfDb_Reset
• iqrfDb_GetDeviceMetadata
• iqrfDb_SetDeviceMetadata