SST: Replace SST APIs with PSA PS APIs

Refactors the SST non-secure interfaces, secure API, veneers and
manifest to implement the PSA Protected Storage specification. Adds a
stub implementation for the new SST APIs; another patch will add the
final implementation.

Change-Id: Id62eb82c9d33afd2114962ab1994d567cd81e4f7
Signed-off-by: Jamie Fox <jamie.fox@arm.com>
36 files changed