GUAC-931, GUAC-942: Add guacHistory service, replacing legacy GuacamoleHistory object.
GUAC-932: Remove use of localStorageUtility where possible. Use cookies for auth data.
GUAC-932: Remove localStorageUtility entirely.
GUAC-932: Save thumbnail upon disconnect.
GUAC-932: Dynamic "src" attribute for img tag should be "ng-src".