fixes #6532
# What does this PR do ?

See issue https://github.com/NVIDIA/NeMo/issues/6532

**Collection**: [Note which collection this PR will affect]
tokenizers

# Changelog 
- See comments in the Issue https://github.com/NVIDIA/NeMo/issues/6532

# Usage
* You can potentially add a usage example below

```python
from nemo.collections.common.tokenizers.tabular_tokenizer import TabularTokenizer
from nemo.collections.common.tokenizers.column_code import ColumnCodes

END_OF_TEXT = '<|endoftext|>'
NEW_LINE = '\n'
DELIMITER = ','

# see example of tab_structure and example arrays here: 
# https://github.com/NVIDIA/NeMo/pull/6533/files#diff-2eb09eb882bbc75d60d887b51950ed0fb3331d5c4248e9e0b0ec0a566609c041R133

column_codes = ColumnCodes.get_column_codes(tab_structure, example_arrays)
tabular_tokenizer = TabularTokenizer(column_codes, special_tokens=[NEW_LINE, END_OF_TEXT], delimiter=DELIMITER)
token_ids = tabular_tokenizer.encode(doc['text'])
output = tabular_tokenizer.decode(token_ids)
```

# Before your PR is "Ready for review"
**Pre checks**:
- [x] Make sure you read and followed [Contributor guidelines](https://github.com/NVIDIA/NeMo/blob/main/CONTRIBUTING.md)
- [x] Did you write any new necessary tests?
- [x] Did you add or update any necessary documentation?
- [ ] Does the PR affect components that are optional to install? (Ex: Numba, Pynini, Apex etc)
  - [ ] Reviewer: Does the PR have correct import guards for all optional libraries?
  
**PR Type**:
- [x] New Feature
- [x] Bugfix
- [ ] Documentation

If you haven't finished some of the above items you can still open "Draft" PR.


## Who can review?

Anyone in the community is free to review the PR once the checks have passed. 
[Contributor guidelines](https://github.com/NVIDIA/NeMo/blob/main/CONTRIBUTING.md) contains specific people who can review PRs to various areas.

# Additional Information
* Related to # [(issue)](https://github.com/NVIDIA/NeMo/issues/6532)
