Doc: Updated the information about OpenSSL support

The developers should know the two different options they
have, if they want to use OpenSSL features in their
application. Also mentioned about the QSslSockect static
member functions that can be used to query the target for
SSL support, and made a few editorial corrections.

Change-Id: I705910e08c267b77c46f162232341118685bfba8
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@theqtcompany.com>
Android: Add note about loading order when overriding deployment

When you use the ANDROID_DEPLOYMENT_DEPENDENCIES variable, you
are technically overriding the whole library selection procedure
with your own. This is made as a fail safe, so there is as little
magic as conveniently possible. This means that the order of the
listed libraries is significant.

Change-Id: Id85e69c45bfa022a1f3320423a7bccb99def6d18
Reviewed-by: Venugopal Shivashankar <venugopal.shivashankar@digia.com>