Packaging

[mumichae]

Add functionality to compute trajectory score per batch and take the mean and not compute the score overall.

• [x] Rename package name scIB to scib ! This will break old code, so all uses of scIB have to be renamed for this version
• [x] Move code from setup.py to setup.cfg
• [x] Move requirements.txt and requirements_extra.txt moved to setup.cfg
• [x] rename mixed case functions
• [x] integrate #273
• [x] Allow optional installs
• [x] integrate #274 (manually)
• [ ] Major Version bump
• [x] integrate in scib-pipeline
• [x] integrate in neurips