Default timout of 30secs for ConfigRetriever

Default timout of 5sec for use by Transporter (ports etc).

And Ndb_cluster_connection::set_timeout() api for setting timeout from
NDBAPI applications. Should be called before connect. e.g.

c.set_timeout(4200);
c.connect();

Index: ndb-work/storage/ndb/include/mgmcommon/ConfigRetriever.hpp
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