Improve dataset import

[pascal-pfeiffer]

• User can now select which problem type the dataset should be used for during import. closes [FEATURE] Add ability to specify dataset problem type during data import #690
• Nested options such as DPO specific settings will appear automatically.
• Nested options now include system prompt column. closes [CODE IMPROVEMENT] Show system column field during dataset import #338
• Updated documentation

import_dataset-2024-05-22_13.24.24.mp4

[sherenem]

LGTM, thanks!

[psinger]

LGTM!

Only odd thing is that system is chosen as the default prompt column in dpo.
Could we change that?

[pascal-pfeiffer]

done