Careful identification of "dashboards"

@mhoeber , this is just cleanup. This came out of the issue that Alison Kuryla's course team had finding "dashboard" in the docs. The JIRA item in the name is for any changes for course re-run to the "My Courses" dashboard, and pointed at 2. There aren't any visible changes, so I spent a half hour going through and identifying the various dashboards in text for Alison instead. And found a couple missed "New Beta Instructor Dashboard" references too -- yuck!
yes. The distinction is that course teams working in Studio see a page titled "My Courses" when they log in. This is commonly referred to inside and out of edX as the Studio "dashboard". Students (and staff) who log in the edge or edx.org and/or click the "dashboard" button see a page labeled "Current Courses". So you think it's misleading to see the current courses *for which you are registered*? Each course has a clearly labeled start date (or archived indicator).