Merge Publications and publications index and view

Fixes

Partially addresses #122 (closed)

Description

This PR contains the following functionality for the publications data:

• Index page for listing publications.
• View page for the selected publication.
• Merge publications feature for cleaning the publications data.

Type of PR

This PR is a feature.

Tests

Pages to test:

• /admin/publications: Test the filters for publications and the view page for publications accessed through the same page.
• /admin/publications/merge-select: Filter publications and select some publications from the results and merge them.