New env values to be sent to tmc-sandbox

[jamo]

I propose that we shall share following information in following env variables to the sandbox

• TMC-USER-ID
• TMC-USERNAME
• PASTE

The need for user id and name will be relevant if generating stuff as part of the tests, such as photoshop images or audio (exercises from our courses)
And for paste we can make some wepa exercises not to give out points when it is submitted as paste. though for this one there might be nicer solutions.