bsp: Align corstone1000 image configuration with mender

Aligns IMAGE_FSTYPES and other mender related configuration for corstone1000 platform as mender recipes already sets some of these configurations. Additionally, Corstone1000 capsule key and certificate files are already installed by u-boot recipe and mender build triggers firmware-deploy task again to copy these binaries which causes an issue. This commits also removes capsule key and certification for corstone1000 for mender builds.

Signed-off-by: Emekcan Aras Emekcan.Aras@arm.com