Push samples to dataset on hub without having the dataset locally
### Feature request

Say I have the following code:

```
from datasets import Dataset
import pandas as pd
new_data = {
    "column_1": ["value1", "value2"],
    "column_2": ["value3", "value4"],
}
df_new = pd.DataFrame(new_data)
dataset_new = Dataset.from_pandas(df_new)
# add these samples to a remote dataset
```
It would be great to have a way to push dataset_new to a remote dataset that respects the same schema. This way one would not have to do the following:
```
from datasets import load_dataset
dataset = load_dataset('username/dataset_name', use_auth_token='your_hf_token_here')
updated_dataset = dataset['train'].concatenate(dataset_new)
updated_dataset.push_to_hub('username/dataset_name', use_auth_token='your_hf_token_here')
```





### Motivation

No need to download the dataset.

### Your contribution

Maybe this feature already exists, didnt see it though. I do not have the expertise to do this.