This includes:
- a new data-structure 'StaticHeteroGraphTemporalSignal' that works like 'StaticGraphTemporalSignal' but with troch_geometric HeteroData objects as snapshots; instead of np arrays, dictionaries wirth key(node/edge types as strings)/value(indices/features as np arrays) are expected
- code tests for the new data-structure
- documentation for the new data-structure

This includes:
- a new data structure, that represents PyG HeteroDataBatch snapshots for static heterogeneous graphs with temporal signals
- documentation
- tests

edge tests
edge index tests
additional attributes None test

edge test
edge weights test
additional attributes None test
batch assigned test

- new data structure that works like DynamicGraphStaticSignal but with PyG HeteroData objects
- tests
- documentation

- data structure that works like DynamicGraphStaticSignal but with PyG HeteroData Batches
- tests
- documentation

- new data structure that works like DynamicGraphTemporalSignal but with PyG HeteroData objects
- tests
-documentation

- data structure that works like DynamicGraphTemporalSignalBatch but with PyG HeteroData Batches instead
- tests
-documentation