New lesson: Sessions

[MaoShizhong]

Because

As part of the Node revamp's 2nd milestone

This PR

• Adds a new lesson for session-based auth to come after the cookies lesson (https://github.com/TheOdinProject/curriculum/pull/28974)

Issue

Closes #28847

Additional Information

Pull Request Requirements

• [x] I have thoroughly read and understand The Odin Project curriculum contributing guide
• [x] The title of this PR follows the location of change: brief description of change format, e.g. Intro to HTML and CSS lesson: Fix link text
• [x] The Because section summarizes the reason for this PR
• [x] The This PR section has a bullet point list describing the changes in this PR
• [x] If this PR addresses an open issue, it is linked in the Issue section
• [x] If any lesson files are included in this PR, they have been previewed with the Markdown preview tool to ensure it is formatted correctly
• [x] If any lesson files are included in this PR, they follow the Layout Style Guide