CTelegramConnection: Several numbers initialization moved to proper places.

SessionId generation now happens on authState >= AuthStateSuccess.
Previouse session was generated on dh-authorization, which is skipped
in "session restore" case.

ClientNonce and rsaKey initialization moved to initAuth(), as they are
needed only for dh-authorization and can be skipped on "session restore".
CTelegramConnection: Added methods to get and set some auth variables.

Added setAuthKey(), setServerSaltArray() and serverSaltArray().
authKey() Already exists.

authKey and server salt.
CTelegramConnection: Reimplemented authentication initialization.

If authKey is not empty on connected signal, set auth state to Signed.