Set isSMB property of SMB treatments uploaded to Nightscout

[cascer1]

Is your feature request related to a problem? Please describe.
To support cleaner rendering code of SMBs in Nightscout, it would be useful to set the isSMB property of SMB treamtents uploaded to nightscout, like AndroidAPS does.

Describe the solution you'd like
Currently, the nightscout code checks for an insulin amount, carb amount, and uploader name when determining whether to render a bolus as SMB. Instead, it could simply check the isSMB property. For this, we need to include this property when uploading SMB treatments to Nightscout.

Additional context

The rendering code change is proposed in nightscout/cgm-remote-monitor#4771

We can remove the first part of the if statement and simply check for isSMB if this feature is implemented in OpenAPS.

[cascer1]

Closing issue because I realized the stateless design of OpenAPS makes it impossible to reliably determine wether or not a bolus was an SMB after the fact.