### Description
This PR is to simplify our blog updating process in order to make sure
it stays up to date. I have added a tempalte and a json source where
blogs can be easily added. I have removed the images from the blogs, and
deleted the old images. Additionally we decided to remove twitter from
the header.
https://cassiebreviu.github.io/onnxruntime/blogs.html
### 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. -->
### Description
Use a shared file for the onnxruntime.ai website nav bar instead of
implementing on each page.
### Motivation and Context
Simplifies site updates.
Changes staged at https://prasanthpul.github.io/onnxruntime/
