[C++] Provided more options in CSV reader's `ParseOptions` and `ReadOptions`

### Describe the enhancement requested

I hope that the following new features to be added to the CSV Reader:

- [x] Allow null padding for rows with fewer columns #50925
- [x] Allow ignoring extra columns in rows with more columns #50967
- [ ] Allow inferring the number of columns based on the longest row read by the `BlockParser`
- [ ] Allow the CSV Reader to accept multi-character delimiters #51275

I have already implemented these features on my local environment, and I plan to submit the PRs within a week.

cc @pitrou

### Component(s)

C++