CLC-3612 Remove /api/my/refresh endpoint and related code

https://jira.ets.berkeley.edu/jira/browse/CLC-3612

MyRefreshController and its endpoint, /api/my/refresh, is obsolete (it was part of the old live updates functionality). Remove it and its related code (including the client-side refreshService).

Christian should review the UI part of this.
Merge pull request #2440 from chikoon/CLC-3612-remove-api-my-refresh

CLC-3612 Remove /api/my/refresh endpoint and related code