Update RTD (CPS-1515: Spike: Support Multiple CM-Handles for NCMP Get Operation)

- Added information about data operation NCMP endpoint and kafka event
  details.
- Re-structured "CPS-Events" and "Modeling" page.

Issue-ID:CPS-1785

Signed-off-by: sourabh_sourabh <sourabh.sourabh@est.tech>
Change-Id: I2b077ccd7ccd6144a8f9f2183d927f922075f532
Signed-off-by: sourabh_sourabh <sourabh.sourabh@est.tech>
diff --git a/docs/cps-ncmp-message-status-codes.rst b/docs/cps-ncmp-message-status-codes.rst
new file mode 100644
index 0000000..99d802f
--- /dev/null
+++ b/docs/cps-ncmp-message-status-codes.rst
@@ -0,0 +1,41 @@
+.. This work is licensed under a Creative Commons Attribution 4.0 International License.
+.. http://creativecommons.org/licenses/by/4.0
+.. Copyright (C) 2023 Nordix Foundation
+
+.. DO NOT CHANGE THIS LABEL FOR RELEASE NOTES - EVEN THOUGH IT GIVES A WARNING
+.. _dataOperationMessageStatusCodes:
+
+
+CPS-NCMP Message Status Codes
+#############################
+
+    +-----------------+------------------------------------------------------+-----------------------------------+
+    | Status Code     | Status Message                                       | Feature                           |
+    +=================+======================================================+===================================+
+    | 0               | Successfully applied changes                         | Data Operation                    |
+    +-----------------+------------------------------------------------------+-----------------------------------+
+    | 1               | successfully applied subscription                    | CM Data Notification Subscription |
+    +-----------------+------------------------------------------------------+-----------------------------------+
+    | 100             | cm handle id(s) is(are) not found                    | Data Operation                    |
+    +-----------------+------------------------------------------------------+-----------------------------------+
+    | 101             | cm handle id(s) is(are) in non ready state           | Data Operation                    |
+    +-----------------+------------------------------------------------------+-----------------------------------+
+    | 102             | dmi plugin service is not responding                 | Data Operation                    |
+    +-----------------+------------------------------------------------------+-----------------------------------+
+    | 103             | dmi plugin service is not able to read resource data | Data Operation                    |
+    +-----------------+------------------------------------------------------+-----------------------------------+
+    | 104             | partially applied subscription                       | CM Data Notification Subscription |
+    +-----------------+------------------------------------------------------+-----------------------------------+
+    | 105             | subscription not applicable for all cm handles       | CM Data Notification Subscription |
+    +-----------------+------------------------------------------------------+-----------------------------------+
+    | 106             | subscription pending for all cm handles              | CM Data Notification Subscription |
+    +-----------------+------------------------------------------------------+-----------------------------------+
+
+.. note::
+
+    - Single response format for all scenarios both positive and error, just using optional fields instead.
+    - status-code 0-99 is reserved for any success response.
+    - status-code from 100 to 199 is reserved for any failed response.
+
+
+