Prepare deployment functions

Started to implement an anndata cellxgene preparation function as discussed in #94 (closed).

So far I focused on preparing the anndata for deployment but the issue also mentions (see the notebook) mamplan creation. Since the related code seems outdated we should discuss if this is needed and how it should be implemented. Hence, why I have skipped it.

TODO

• create mamplan function?
• tests

Fixes #94 (closed)