Restart OPUS, when it does not record any measurements

[dostuffthatmatters]

When the macro is running, the number of files should increase at a certain path.

The requires adding two config items:

• opus.measurementspath = .../MEASUREMENTS/%Y%m%d
• opus.restart_when_no_measurements = True/False

This should be disabled by default, hence the path can be empty. No error should be thrown if there is no path, only a warning.