Add new region endpoints in secapps.md

[YongchangCui]

In docs/manageapps/secapps.md , we had three region listed.
US-South: secure.us-south.bluemix.net
EU-GB: secure.eu-gb.bluemix.net
AU-SYD: secure.au-syd.bluemix.net

Now we have two new regions to be added, these are
US-East: secure.us-east.bluemix.net
EU-DE: secure.eu-de.bluemix.net

Please help to update the document. Thanks.

[mekaufman]

Added eu-de and requested an updated build. Holding off on the us-est until it is fully live and announced.