Path assertions and create output paths automatically

[Tobiaspk]

Currently, Segger crashes if the output path does not exist. It also returns a non-informative error when the input directory is empty or incorrectly specified. For example, an empty input directory produces:

ValueError: Could not infer platform from data directory: CosMx sample directory must contain exactly 1 file or directory matching *_tx_file.csv, but found 0., [Errno 2] No such file or directory: 'experiment.xenium', [Errno 2] No such file or directory: 'experiment.xenium', .

Suggestion, open to feedback

• If output path does not exist - Create it
• If input path is empty, or not a single file matches any platform - Identify this and raise a proper exception