templates: Use HAL startup file and own linker scripts for TF-M

The default NS (non-secure) startup file and linker scripts from TF-M
are very minimal and intended to be just enough for running TF-M's
integration tests. The startup file does not provide handlers for many
peripherals supported by MCU-Driver-HAL, making it impossible to use
those peripherals. The linker scripts are not customizable so it is
impossible to use a larger heap or define extra symbols expected by some
RTOSes such as ThreadX. So in our TF-M example and test, switch to use
the startup file from the HAL implementation and generate linker scripts
from the templates like the other example.

Signed-off-by: Lingkai Dong <lingkai.dong@arm.com>