Make metadata elements clickable

[nuest]

All identifiers should be links. Please be aware of https://orcid.org/content/journal-article-display-guidelines and suggest to re-use the DOI logo from the link above the paper, too. We can even use https://spdx.org/licenses/ to derive links to the license texts from the license identifier.

• [x] DOI clickable
• [x] Licenses clickable
• [x] ORCID clickable

[njakuschona]

The requested elements are now clickable and the requested website will open in a new tab. To get the URL of the Licenses I used the URL which is saved in the licenses.json