initial inclusion of Zotero
Summary: Zotero is a free, easy-to-use tool to help you collect, organize, cite, and share your research sources. Resolves T685
Test Plan: build & install, add file, export "My library.bib"
Reviewers: Triage Team, kyrios123, Girtablulu
Reviewed By: Triage Team, kyrios123, Girtablulu
Subscribers: Girtablulu, joebonrichie, kyrios123
Maniphest Tasks: T685
Differential Revision: https://dev.getsol.us/D12784