Update docs explaining CA export format changes.
Update docs explaining CA export format changes.

sokoow/teleport,yacloud-io/teleport,gravitational/teleport,aashley/teleport,sokoow/teleport,aashley/teleport,tidalf/teleport,tidalf/teleport,sokoow/teleport,gravitational/teleport,gravitational/teleport,suedadam/teleport,sokoow/teleport,yacloud-io/teleport,yacloud-io/teleport,aashley/teleport,gravitational/teleport,aashley/teleport,suedadam/teleport,suedadam/teleport,tidalf/teleport,tidalf/teleport,yacloud-io/teleport,sokoow/teleport,suedadam/teleport,sokoow/teleport,suedadam/teleport,tidalf/teleport,yacloud-io/teleport,gravitational/teleport,gravitational/teleport,aashley/teleport,yacloud-io/teleport,yacloud-io/teleport