add dask suppport and valis alignment (#69)

- add dask support for loading larger than RAM transcript dataframes
- refactor alignment methods (decouple alignment matrix loading from alignment)
- add Valis registration support to the processinig pipeline
- cleanup of unused functions/impots
- hestcore 1.0.3 -> 1.0.4 (better documentation)

re-add bench

resolve spatialdata conversion exception

fix bench gene panel (#14)

Update README.md