Fix download to actually download, and clicking on artifact name to show OR download.

In scope:

• Clicking on download should always result in a download
• Clicking on artifact name should open the artifact in a new tab (as now) IFF the browser knows how to render (ie the current behavior for download link should be transferred to name)

Out of scope:

• Moon landing.

HTML5 download attribute (as mentioned below) is probably fine to use.

Reproduction notes:

Procedure

1. Browse to a build that has produced artifacts (test.html, test.blob).
2. Click on test.html (it will be viewed)
3. Click on test.blob (it will be downloaded)

Expected

Clicking on the artifact "download" link should always download the artifact. A download (and filename) should be forced using Content-Disposition (from the server) or a HTML5 download=FILENAME attribute (client).

Clicking on the artifact name should do what the current download icon does - ie download or show (if the browser knows how to render the content type).

How this is implemented depends if server side header or html5 download is used.

Actual

Some mime-types are downloaded, some are viewed

*.html are opened for view, *.unknown are downloaded.