samples: tfm_integration: Add TFM IPC sample app

This commit adds a minimal sample application showing how
TF-M can be used in IPC mode, with Zephyr providing the
non-secure processing environment image, and linking against
the PSA APIs implemented in TF-M.

This commit also include work from the commit quoted below,
which is included here for attribution purposes:

    tfm_ipc: cmake: now using tfm_ipc library created by TF-M module

    This commit removes the need for local knowledge of the TF-M
    repository structure and files.

    Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>

Signed-off-by: Karl Zhang <karl.zhang@linaro.org>