Extend exception handler to report details

On failed requests, log and return details in the HTTP error response.
Extend documentation to pull in the OpenAPI specification document.
On store, overwrite ID in body with ID from path to ensure consistency.

Signed-off-by: Lott, Christopher (cl778h) <cl778h@att.com>
Change-Id: I630360bcf90c80b84392c6afb1e59347fccd13ef
diff --git a/docs/overview.rst b/docs/overview.rst
index 73f8ed9..ac751e7 100644
--- a/docs/overview.rst
+++ b/docs/overview.rst
@@ -1,19 +1,20 @@
 .. This work is licensed under a Creative Commons Attribution 4.0 International License.
 .. SPDX-License-Identifier: CC-BY-4.0
 
-A1 Mediator
+A1 Overview
 ===========
 
+The RAN Intelligent Controller (RIC) Platform's A1 Mediator component listens for policy
+type and policy instance requests sent via HTTP (the "northbound" interface),
+and publishes those requests to running xApps via RMR messages (the "southbound" interface).
+
 Code
 ----
+
+Code is managed in this Gerrit repository:
+
 https://gerrit.o-ran-sc.org/r/admin/repos/ric-plt/a1
 
-API
----
-
-You can see the API (OpenAPI3 spec) at ``a1/openapi.yml``. You can also
-see the “pretty” version if you run the container at
-``http://localhost:10000/ui/``.
 
 Policy Overview
 ----------------