Add HTML meta tags for the DOI and citation metadata

HTML meta tags for citation metadata (identifier, title, authors, etc.) are important to integrate with reference managers and indexers such as Google Scholar.

## Describe the solution you'd like
Will add citation metadata following the Zenodo implementation and [Google Scholar Guidelines](https://scholar.google.com/intl/en/scholar/inclusion.html#overview). Most importantly is a meta tag for the DOI so that Zotero and other reference managers can harvest metadata via a lookup of DOI metadata.

## Describe alternatives you've considered
Embedded schema.org metadata will not be picked up by reference managers and Google Scholar.

## Additional context
The Zenodo implementation can provide guidance.