Update readme and add roadmap

[XuyaoWang]

Description

Update readme and add roadmap

Motivation and Context

Why is this change required? What problem does it solve?
If it fixes an open issue, please link to the issue here.
You can use the syntax close #1314520 if this solves the issue #15213

• I have raised an issue to propose this change (required for new features and bug fixes)

Test

Please test your changes by running the following command:

cd scripts
bash test/test_text_to_text.sh ./opt PATH_TO_OUTPUT_ROOT_DIR

Here, ./opt is the directory containing the test scripts for the opt model, and PATH_TO_OUTPUT_ROOT_DIR is the path to the output root directory. The test scripts will save ~1GB data to the output root directory and delete it after the test. Please ensure you have enough space on your disk.

Lint

Please run the following command in the root directory to check your code style:

pip install pre-commit
pre-commit run --all-files

Types of changes

What types of changes does your code introduce? Put an x in all the boxes that apply:

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds core functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation (update in the documentation)

Checklist

Go over all the following points, and put an x in all the boxes that apply.
If you are unsure about any of these, don't hesitate to ask. We are here to help!

• I have read the CONTRIBUTION guide. (required)
• My change requires a change to the documentation.
• I have updated the tests accordingly. (required for a bug fix or a new feature)
• I have updated the documentation accordingly.

[Kass123777]

LGTM!