[file_import] Set type of imported columns

[Dynnammo]

Using dtypes

Example
# dtypedict = {}
# for i,j in zip(df.columns, df.dtypes):
# if "object" in str(j):
# dtypedict.update({i: sqlalchemy.types.String})
# elif "datetime" in str(j):
# dtypedict.update({i: sqlalchemy.types.DateTime})
# elif "float" in str(j):
# dtypedict.update({i: sqlalchemy.types.FLOAT})
# elif "int" in str(j):
# dtypedict.update({i: sqlalchemy.types.INT})
# else:
# raise NotImplementedError("column type not handled")