Have both IP policy doc tress under the same section

The IP policy and implementation guidelines are moved from being
standalone root entries to being part of a new section entitled
"Intellectual Property Compliance Policy". This makes the root
documentation level a bit cleaner.

Signed-off-by: Andrei Gherzan <andrei.gherzan@huawei.com>

index.rst

@@ -28,7 +28,6 @@ headphones, and AR/VR glasses.
    meta-ohos/index
    readme/README
    contributing/README
-   ip-policy_implementation-guidelines/index
-   ip-policy_policy/index
    ci/index
+   ip-policy/index
    code-of-conduct

ip-policy/index.rst

+.. SPDX-FileCopyrightText: Huawei Inc.
+..
+.. SPDX-License-Identifier: CC-BY-4.0
+
+Intellectual Property Compliance Policy
+#######################################
+
+.. toctree::
+   :maxdepth: 1
+
+   ip-policy_policy/index
+   ip-policy_implementation-guidelines/index

ip-policy/ip-policy_implementation-guidelines

+../../ip-policy/implementation_guidelines/source/
\ No newline at end of file

ip-policy/ip-policy_policy

+../../ip-policy/policy/source/
\ No newline at end of file

ip-policy_implementation-guidelines

-../ip-policy/implementation_guidelines/source
\ No newline at end of file

ip-policy_policy

-../ip-policy/policy/source/
\ No newline at end of file