doc: consolidate api status and guidelines

Move all docs related to APIs and the guidelines around them into one
page.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>

doc/development_process/index.rst

@@ -12,7 +12,6 @@ Development Model
    code_flow
    dev_env_and_tools
    issues
-   api_lifecycle
    communication
    documentation
 

doc/guides/index.rst

@@ -12,7 +12,6 @@ User and Developer Guides
    bluetooth/index.rst
    build/index
    coding_guidelines/index
-   design_guidelines.rst
    c_library
    ../README.rst
    documentation/index

doc/reference/api/index.rst

@@ -0,0 +1,12 @@
+.. _api_status_and_guidelines:
+
+API Status / Guidelines
+#######################
+
+.. toctree::
+   :maxdepth: 1
+
+   overview.rst
+   api_lifecycle.rst
+   design_guidelines.rst
+   terminology.rst

doc/reference/index.rst

@@ -6,8 +6,7 @@ API Reference
 .. toctree::
    :maxdepth: 1
 
-   overview.rst
+   api/index.rst
-   terminology.rst
    audio/index.rst
    misc/notify.rst
    bluetooth/index.rst