FREYA-1552: Add publications page

[senthil10]

📋 Summary

This PR adds publications page (app) to the new portal.

🛠️ Changes Made

• Added new django app with model, view, template, etc

🔍 Notes for Reviewers

• To test this locally, add the following to your .env file

EUROPE_PMC_API_URL=https://www.ebi.ac.uk/europepmc/webservices/rest/search?sortBy=FIRST_PDATE_D+desc&resultType=core&format=json&pageSize=10
EUROPE_PMC_WEB_URL=https://europepmc.org/search

• Do a django DB mirgration to add the new table to DB
• Add some pathogens with query strings in the DB (via django admin page). You can test by adding one, many or all pathogens that are listed in the current pathogens portal (see the config file). Each pathogen should an individual entry/record in the DB.
• After this, it is the usual. Just go to http://localhost:8000/publications/

Have used htmx to lazy load the publications list on the new page load to give a "fast load" feeling. htmx is also used to change the list based on selected pathogen from the sidebar.

✅ Checklist

• PR title follows the pattern: FREYA-XXXX: Clear and short description
• Jira / Github issue is linked in description
• Assignee is selected
• Code and content adhere to conventions
• Automated checks pass
• Reviewer is selected when the PR is marked as ready for review

🔗 Jira Issue

Closes: FREYA-1552