minor fix allowing to set header row number in csv_reader

added arg to csv reader allowing to specify header row (#41)

* Add header parameter to Handler class for CSV reading

- Introduced an optional `header` parameter in the `Handler` class to specify the header row of the CSV file when reading chromatographic data. This enhances flexibility in handling different CSV formats.

* Refactor concentration unit handling in Molecule class

- Removed logger warnings and replaced the unit validation logic to directly assert the concentration unit name matches the expected unit string. This simplifies the error handling process and improves clarity in unit validation.

* Add header parameter to GenericCSVReader for CSV file reading

- Updated the GenericCSVReader class to include an optional `header` parameter in the `read` method, allowing users to specify the header row when reading CSV files. This change enhances flexibility in handling various CSV formats.

* rerun examples

* v 0.10.1

* rerun tests