Beta Plugin: Add a Settings link to the Plugin table view

If we add a Settings link into the plugins table view, it should be detected and added in Calypso as well, which will give a slightly better flow for people who install this plugin from within Calypso:

Add a link here;

which should then show up here (example taken from Akismet plugin view in Calypso);

Locate the plugin table view and inspect how Calypso detects plugin-provided links, using the screenshots and the plugin table view described in the issue as the starting points. The work is done when a Settings link appears in that table and is detected and shown in Calypso as described.

Written by the indexing model from the issue text.