Fix AccountInfo.has_avatar_info() that wrongly always returns true

AccountInfo.has_avatar_info() checks whether the AccountInfo contains
an avatar field. This is currently always true. Set this field on
server side only if an avatar provider is installed.

Change-Id: Ib73bd925d70d5049688ae9a57a058645b2cbda41
Signed-off-by: Edwin Kempin <edwin.kempin@sap.com>
SideBySide2: Hide reviewed checkbox if not signed in

Users cannot mark a file as reviewed unless they are signed in, as the
server needs the user identity to store the reviewed flag. The checkbox
is hidden on ChangeScreen2 for anonymous users, so hide it in SBS2.

Change-Id: I96605222fab5ab0cb64c157b51dc4ca92ec4732d
SideBySide2: Do not offer 'r' keybinding to anonymous users

Anonymous users cannot mark a file as reviewed, as the server
has no way to track the stored flag. Disable the keybinding
so it does not appear in the help dialog.

Change-Id: I415a24754d1b4b5120b5b40e074ee697cf921b52
Merge branch 'stable-2.9'

* stable-2.9:
  SideBySide2: Do not offer 'r' keybinding to anonymous users
  SideBySide2: Hide reviewed checkbox if not signed in
  Fix AccountInfo.has_avatar_info() that wrongly always returns true