crypto: decouple the PSA Crypto interface from TF-M flags

This patch cleanup the PSA Crypto interface headers files and
decouples it from TF-M build flag dependencies. The
`psa_key_attributes_t` struct definition previously depended
on various config options. The struct now only has fields
which can be set and read by the client. Hence the client
view of the structure is now defined separately in the
crypto_client_struct.h header.

The platform dependant definitions of the PSA Crypto types
are fixed and hence the crypto_platform.h header is removed
and the contents are moved to other PSA crypto headers.

The previous intermediate solution for hiding the type
differences between crypto server and client view via
`psa_client_core_key_attributes_t` is now removed.

Change-Id: I2644b5a2da3babe561c569ebf5690b3daa576a12
Signed-off-by: Soby Mathew <soby.mathew@arm.com>