Currently we use the page + action as a section name, and then list
shortcuts as entry values:

  [detail-page.add-comment]
  shortcut-0 = c
  shortcut-1 = f

The new format uses the page as the section name, with the shortcut
as the entry key, and action as the entry value:

  [detail-page]
  c       = add-comment
  f       = add-comment

This makes it more clear at a glance what key shorts are configured

Existing config files will be transparently re-writen on first
startup with the new format.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>