support multiple data types

[stefaniereuter]

currently everything is cast to double (was necessary because of an adios bug) but it should be fixed in new adios2.9 version. So include a query for correct datatype and on server and receiver side

[tobyjamez]

Needs to be added in the python side first, then can be reinstated on the server. Important to be able to send single-precision where appropriate. Also maybe ints.

[tobyjamez]

data_cache.py:173 in function load_from_cache(): convert C++ types to python types

wrap in some kind of type_dict = {"double": float64} etc

[tobyjamez]

wan.py:243 in function receive_dict_arrays hacky replace("_t", "")
and likely appears in more routines. find them and change them