Integrate PurlDB in the UI navigation

[pombredanne]

Here is a usecase that I would like to see supported: I imported an SBOM and while I navigate packages, there is a package that I would like to dive into.
I would like to:

1. live lookup and display the PurlDB details
2. if necessary, have the PurlDB fetch metadata and scan the package (and eventually all the packages in its set) and also report this in the SCIO context

This could be without updating the local data. Later one I would like also to update selectively, but this is may be best done in DejaCode.

[tdruez]

1. live lookup and display the PurlDB details

@pombredanne A new PurlDB tab is now displayed in the package details view when the PurlDB is properly defined in the app settings.

2. if necessary, have the PurlDB fetch metadata and scan the package (and eventually all the packages in its set) and also report this in the SCIO context

This process should happen on the PurlDB side. Any PURL requested in the PurlDB REST API that does not have a local match should be placed in a queue to be mined, scanned, and added to the PurlDB.