otr: small fixes in fingerprint exchange page

Signed-off-by: Rafał Malinowski <rafal.przemyslaw.malinowski@gmail.com>
otr: added stub of Question and Answer wizard page

Signed-off-by: Rafał Malinowski <rafal.przemyslaw.malinowski@gmail.com>
otr: ensure valid trust levels at start of application

Signed-off-by: Rafał Malinowski <rafal.przemyslaw.malinowski@gmail.com>
otr: allow sending question and answer to peer

Signed-off-by: Rafał Malinowski <rafal.przemyslaw.malinowski@gmail.com>
otr: fix trust level of non-otr contacts

Signed-off-by: Rafał Malinowski <rafal.przemyslaw.malinowski@gmail.com>