Debug messages printed to stdout

There is a forgotten debug print in robofish.io.file:

for c in calendar_time_points:
    print(type(c))

https://git.imp.fu-berlin.de/bioroboticslab/robofish/io/-/blob/master/src/robofish/io/file.py#L209

causes:

<class 'str'>
<class 'str'>
<class 'str'>
...
<class 'str'>
<class 'str'>