Feat: deletion of tfs via flatbuffers service

[mmeijerdfki]

This PR adds the ability for a client to request the deletion of a range of TFs by specifying timespan, parent frame and child frame. Refer to seerep_com/README.md and examples/python/gRPC/tf/gRPC_fb_deleteTfs.py for more information.
The feature in combination with TransferTransformStamped effectively enables the altering of TFs.

Changes and discussion points:

• The spatial index is recreated whenever a stream of TF deletion requests has been sent and TFs were removed
• The complete data of the TFs is read and rewritten to HDF5
• A corresponding example and integration test was created
• Minor simplification of the createQuery interface of fb_helper: builder.CreateString() on uuids is now done in the function
• gRPC_fb_sendImages takes a frame_id and timestamps for its header as parameters to be used for TF tests
• small fix in fb_to_dict.py, when variables weren't set
• variations for the call_get_images_fb in service_manager.py to directly get a python dict
• wrapper functions to the canTransform and transformAABB calls such that DatasetIndexable can be used directly