Pycognaize

- Modify rest.app to make snapshots through a shared volume
- Implement `DataSnap.create` and DataSnap initialization through a shared volume
- Modify DataPipe in order to be inherited by DataSnap
- Add cloudstorageio to requirements
- Add SnapshotPathMissingException and SnapshotExistsException
- Remove IQ_DATASNAP_URL and add IQ_SNAP_STORAGE_PATH to EnvConfigEnum
- Remove igraph dependencies from Dockerfile
- Add DATASET_TYPE to DataSnap

- Allow to import dataset types from `pycognaize.datasets`
- Add DataSnap
- Refactor the package structure

- Add Dockerfile and build.sh for building docker image with hash

- Fix DEFAULT_DB error handling, add rest API for snap

- Add raw and construct_from_raw methods
- Add data snap serialization and deserialization