#165 Confirmation dialog

@mobreza I've done. You can check it in console with this code:

confirm(
    `Delete dataset 'foobar'?`,
    {
        description: `Deleting the dataset will remove all associated data.`,
        confirmLabel: 'Delete',
        abortLabel: 'Cancel'
    }
)
    .then(() => console.log('ok'))
    .catch(() => console.log('cancel'));

Closes #165 (closed)