Comment 2 for bug 1734174

Changes proposed:

1. Create new DB table ("usr_terms"?) with fields - id[PK], usr, institution, version, time. Will contain reference to site_terms (see bug #1734182) version field of T&C version each user has agreed to for each relevant insitution, and the time they agreed to them.

3. Upon login, fetch most recent T&C version from site_terms, compare with version stored in usr_terms.

2. Redirect users to page to accept updated T&C.

    * Page to list all applicable T&C (site and institutions) in expandable panels.
    * Not yet agreed to (first visit, new institution membership, or T&C updated) T&C panels
      will be expanded.
    * Panels containing T&C already agreed to will be collapsed.
    * Single "Accept" button for accepting all terms.
    * Single "Do not accept" button which, when clicked, will notify relevant admins
      (site and istitution) for further investigation.

3. No other site pages will be accessible until user has agreed to T&C.