Docs: Move build instruction and user guide into technical reference

Move build instruction document and user guide document from getting
started into technical references folder. Rename 'tfm_user_guide.rst'
to 'tfm_run_instruction.rst'. This will make the document structure
more clear for readers.

Signed-off-by: Summer Qin <summer.qin@arm.com>
Change-Id: I69d46151f2cb97c828c1b82775ffd1af9032ed45
diff --git a/docs/contributing/contributing_process.rst b/docs/contributing/contributing_process.rst
index b017c63..002df7e 100644
--- a/docs/contributing/contributing_process.rst
+++ b/docs/contributing/contributing_process.rst
@@ -27,7 +27,7 @@
   - Clone the TF-M code on your own machine from `TF-M git repository
     <https://git.trustedfirmware.org/TF-M/trusted-firmware-m.git>`_.
   - Follow the :doc:`SW Requirements </docs/getting_started/tfm_sw_requirement>`,
-    :doc:`Build Instructions </docs/getting_started/tfm_build_instruction>` and
+    :doc:`Build Instructions </docs/technical_references/instructions/tfm_build_instruction>` and
     :doc:`Coding Guide </docs/contributing/coding_guide>` for the TF-M project.
   - Make your changes in logical chunks to help reviewers. Each commit should
     be a separate review and either work properly or be squashed after the