Support arbitrary URL templates

[joverlee521]

Context

Discussed in dev chat with the context of complying with Pathoplexus data use terms

If displayed on a website or in another database, each sequence should have a direct link to the original sequence page on Pathoplexus, and display the Pathoplexus accession or link to an INSDC database and display the INSDC accession, if available on INSDC.

Description

Instead of adding another hardcoded URL generation to Auspice (i.e. how it adds GISAID and GenBank URLs), we should support arbitrary URL templates via the Auspice JSON.

[victorlin]

Note that for Pathoplexus data use terms, a simple template from the original value does not suffice since the values RESTRICTED/OPEN can't be used as-is to construct the URLs:

• https://pathoplexus.org/about/terms-of-use/restricted-data
• https://pathoplexus.org/about/terms-of-use/open-data

In this case, since there are only 2 values, defining a mapping for each value might be more appropriate.