Remove support for Mozilla Backpack

Tip :  Firefox displays better JSON content (so it's easier to find the fields to check).  Setup As admin verify that badges are enabled in Administration / Site administration / Advanced features. Go to "Site administration / Badges / Badges settings" and set: Badge issuer name to "Issuer1" Badge issuer email address to "issuer@moodle.invalid" Go to "Site administration / Badges / Manage Badges / Add a new badge" and create a badge at site level. Add a criteria to the badge so it can be manually issued by role. Enable the badge. Issue the badge to the admin user. Testing scenario 1: Remove Mozilla backpack references. Login as admin. Access to "Site administration / Badges / Backpack settings". Check selected value for "Active external backpack" is "https://badgr.io". Check there is only one entry in "Active external backpack" list. Check "Default" value for "Active external backpack" is "https://badgr.io". Testing scenario 2: Issues displayed as expected View this user's profile page. Verify that in "Badges from [Moodle instance name] " you now see your local badge. Access to the badge. In the URL, replace badges/badge.php?hash= to badges/assertion.php?b= (the context after hash= should be keept). Add "&action=1" at the end of the previous URL. Check the JSON content displayed contains issuer with the following fields: name, url, email, @context, id, type. Add "&obversion=1" at the end of the previous URL (after &action=1). Check the JSON content displayed contains issuer with a URL to issuer_json.php Open the URL in the issuer field Check the JSON content displayed contains the following fields: name, url, email