Add functionality to leave out the cirrus and water absorption bands from the L2A result.

These bands contain spectral spikes in the L2A result. Since they don´t contain useful information anyways, we could also drop them if not needed by the user.

Steps to do:

• add a corresponding config parameter
• leave out the absorption bands

However, we first need to check if it is programmatically possible to drop these bands alrady in the input reader. This would save processing time but requires compatibility of the downstream algorithms.

@nbohn Could you please check if SICOR could cope with a changed number of input bands?