Importing archive in `core.sqlite_dos` fails

[sphuber]

If the archive contains a Computer, the import will fail with:

Traceback (most recent call last):                                                                                                                                                             
  File "/home/sph/.mambaforge/envs/aiida-py311/lib/python3.11/site-packages/sqlalchemy/engine/base.py", line 1805, in _execute_context
    context = constructor(
              ^^^^^^^^^^^^
  File "/home/sph/.mambaforge/envs/aiida-py311/lib/python3.11/site-packages/sqlalchemy/engine/default.py", line 1457, in _init_compiled
    l_param: List[Any] = [
                         ^
  File "/home/sph/.mambaforge/envs/aiida-py311/lib/python3.11/site-packages/sqlalchemy/engine/default.py", line 1459, in <listcomp>
    flattened_processors[key](compiled_params[key])
  File "/home/sph/.mambaforge/envs/aiida-py311/lib/python3.11/site-packages/sqlalchemy/sql/sqltypes.py", line 3590, in process
    value = value.hex
            ^^^^^^^^^
AttributeError: 'str' object has no attribute 'hex'

It seems like this has to do with the UUID of the Computer instance. Sqlalchemy thinks it is a UUID type and so calls .hex on it, but actually the value is a string. The core.psql_dos models do have the uuid column as a native UUID type, however Sqlite doesn't support that, so when the models are derived from the core.psql_dos backend, the UUID column is converted to CHAR(32). It is not quite clear why sqlalchemy still converts the uuid to a UUID type.