Accepting single value data frame format

[sarahmish]

Currently, dataframes are expected to bin values in each row. However, in a typical scenario, the data is expected to be recorded at each timestamp with one value. process_signal needs to handle the other type of data format.

The means that our dataframe goes from this expected format

  turbine_id        signal_id           timestamp                                             values
0       T001  Sensor1_signal1 2020-01-01 00:00:00  [0.43616983763682876, -0.17662312586241055, 0....
1       T001  Sensor1_signal1 2020-01-01 01:00:00  [0.8023828754411122, -0.14122063493312714, -0....
2       T001  Sensor1_signal1 2020-01-01 02:00:00  [-1.3143142430046044, -1.1055740033788437, -0....
3       T001  Sensor1_signal1 2020-01-01 03:00:00  [-0.45981995520032104, -0.3255426061995603, -0...
4       T001  Sensor1_signal1 2020-01-01 04:00:00  [-0.6380405111460377, -0.11924167777027689, 0....
..       ...              ...                 ...                                                ...

to something like

    turbine_id        signal_id           timestamp    values
0         T001  Sensor1_signal1 2020-01-01 00:00:00   0.43617
1         T001  Sensor1_signal1 2020-01-01 00:00:01 -0.176623
2         T001  Sensor1_signal1 2020-01-01 00:00:02  0.056531
3         T001  Sensor1_signal1 2020-01-01 00:00:04  0.433728
4         T001  Sensor1_signal1 2020-01-01 00:00:06 -0.019152
..         ...              ...                 ...       ...