Refactor to SodarPullBase

[Nicolai-vKuegelgen]

Similarly to SodarIngestBase we should introduce a SodarPullBase class an make all functions that download files from Sodar inherit from that.

This should at least include:

• snappy pull_all_data (Note: this command is not intuitive and should probably be changed/replaced)
• snappy pull_processed_data
• snappy pull_raw_data
• sodar pull_data

Note that snappy pull_data_common and sodar pull_raw_data are currently marked for deprecation.