feat(app): add code to parse app bin headers

Add code in lib/el0_app that is able to iterate over the attached app
bins, and save the header addresses.

Modify the boot code so that the parsing function in lib/el0_app is
called

Also update the build system so that the bin gnerating/bundling scripts
are called on the apps

Change-Id: I97c93edc58bd0fea25770f1d2001c1b2742e1f13
Signed-off-by: Mate Toth-Pal <mate.toth-pal@arm.com>
17 files changed