Export Bibliography from Publications Pages

Fixes

Fixes for #521 (closed) by @shivohamangal

Description

This pr will allow the users to download publications from index and single view pages with all bib formats like bib and ris

Type of PR This PR is a feature.

Technicalities

Tests

1. Goto http://127.0.0.1:2354/publications. Here you will see the "Export Publications" dropdown. try exporting the various formats.
2. If you search for publications using the form and if the results are less than 1000, then you can download all the results, else a modal will be diplayed on clicking the button with a sentence like this: “To download publications in a file format, visit our data repository on Github." with a link.
3. Goto http://127.0.0.1:2354/publications/1 or any other single view. Here too you can download the publication in various formats using the drop-down.

Screenshots

Checklist:

• My pull request has a descriptive title (not a vague title like "Update index.md").
• My pull request targets the phoenix/develop branch of the repository.
• My commit messages follow best practices.
• My code follows the established code style of the repository.
• I added tests for the changes I made (if applicable).
• I added or updated documentation (if applicable).
• I tried running the project locally and verified that there are no visible errors.