eclair/: ECLAIR configs and scripts

Mostly copied from the TF-A implementation, but with some changes for TF-M
already.

Includes external_sources.ecl, a dedicated file for external
sources specification.

Signed-off-by: Paul Sokolovsky <paul.sokolovsky@linaro.org>
Change-Id: Ia092024205f0bc2d350318afdc2aed855dedf091
6 files changed