feat: Backend API for LiveJournal with Cloudinary and IP ban fix

[apoorvajainrp21]

Description

This PR implements the backend controller and API endpoints required for the LiveJournal Auto-Poster. It handles the XML-RPC communication with LiveJournal, manages scheduled posts via MongoDB, and integrates Cloudinary for hosting images embedded in posts.
Implements # (LiveJournal Auto-Poster API)

Related PRS (if any):

This backend PR is related to the #4624 frontend PR.
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Main changes explained:

• Create liveJournalPostController.js: Implemented the postToLiveJournal logic using the XML-RPC protocol.
• Update liveJournalPostController.js: Added Cloudinary integration to upload and host images before embedding them in post HTML.
• Update liveJournalPostController.js: Implemented schedulePost, updateScheduledPost, and deleteScheduledPost to manage delayed publications in the database.
• Update liveJournalPostController.js: Added logic to handle alt text and image title attributes for accessibility and hover effects.
• Update package.json: Added cloudinary and streamifier dependencies.

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How to test:

• check into current branch feature/livejournal-backend-api
• do npm install to install cloudinary and streamifier.
• Ensure your .env file has valid CLOUDINARY_CLOUD_NAME, CLOUDINARY_API_KEY, and CLOUDINARY_API_SECRET values.
• Start the server (npm start).
• Schedule a post and verify it is being posted.

Screenshots or videos of changes:

Note:

Reviewers must run npm install to pull in the new Cloudinary dependencies. Ensure environment variables are set up locally for testing.