serial write/read for Calliope, microbit and arduino

[rbudde]

we need serial write/read for Calliope, microbit and arduino, see #1007

Still missing:

• [x] Write serial implementation in Calliope visitor
• [x] Write serial implementation in Microbit visitor
• [x] Write serial implementation in arduino visitor
• [ ] Write serial implementation in simulation visitor
• [ ] Adding read serial block to all toolboxes
• [ ] Read serial implementation in Calliope visitor
• [ ] Read serial implementation in Microbit visitor
• [ ] Read serial implementation in arduino visitor
• [ ] Read serial implementation in simulation visitor
• [ ] Tests

[bjost2s]

@rbudde , I think it is already available and working for arduinos (only write)

• for simulation we need to discuss the way it will be shown
• for all "read" commands we have to discuss the tools, that we want to support, e.g. extending our apps for bluetooth support.

[bjost2s]

Reopen because several users are asking for serial read().

This would add a convenient option to interact with the devices.