Clean up `CsvFileConnector`

[sebastian-peter]

The following methods in edu.ie3.datamodel.io.connectors.CsvFileConnector seem to do very similar things and can probably be consolidated.

• getIndividualTimeSeriesMetaInformation(UUID timeSeriesUuid)
• buildIndividualTimeSeriesMetaInformation()
• getCsvIndividualTimeSeriesMetaInformation(ColumnScheme... columnSchemes)
• buildCsvTimeSeriesMetaInformation(String filePathString, ColumnScheme... columnSchemes)