[FEATURE] peptide export from feature map for pyOpenMS

[axelwalter]

Description

Peptides assigned to features can be exported together with meta values 'ID_native_id' (feature spectrum id) and 'ID_filename' (primary MS run path of corresponding protein id). Based on these values and feature ID the peptide and feature DataFrames can be merged later.

Checklist:

• Make sure that you are listed in the AUTHORS file
• Add relevant changes and new features to the CHANGELOG file
• I have commented my code, particularly in hard-to-understand areas
• New and existing unit tests pass locally with my changes
• Updated or added python bindings for changed or new classes. (Tick if no updates were necessary.)

How can I get additional information on failed tests during CI:

If your PR is failing you can check out

• http://cdash.openms.de/index.php?project=OpenMS and look for your PR. If you click in the column that lists the failed tests you will get detailed error messages.

Note:

• Once you opened a PR try to minimize the number of pushes to it as every push will trigger CI (automated builds and test) and is rather heavy on our infrastructure (e.g., if several pushes per day are performed).

[axelwalter]

thanks for the review!