Add API Reference for Watcher

This patch set adds API Reference along with some
fixes to documentation. It partially fixes bug #1757423.

Change-Id: I107b4fd5daf40aad63fc13864debbbbc82a9826c

api-ref/source/watcher-api-v1-scoring_engines.inc

@@ -0,0 +1,120 @@
+.. -*- rst -*-
+
+===============
+Scoring Engines
+===============
+
+A ``Scoring Engine`` is an executable that has a well-defined input, a
+well-defined output, and performs a purely mathematical task. That is,
+the calculation does not depend on the environment in which it is running - it
+would produce the same result anywhere.
+
+Because there might be multiple algorithms used to build a particular data
+model (and therefore a scoring engine), the usage of scoring engine might
+vary. A metainfo field is supposed to contain any information which might
+be needed by the user of a given scoring engine.
+
+List Scoring Engine
+===================
+
+.. rest_method::  GET /v1/scoring_engines
+
+Returns a list of Scoring Engine resources.
+
+Normal response codes: 200
+
+Error codes: 400,401
+
+Request
+-------
+
+.. rest_parameters:: parameters.yaml
+
+   - limit: limit
+   - sort_dir: sort_dir
+   - sort_key: sort_key
+
+Response
+--------
+
+.. rest_parameters:: parameters.yaml
+
+    - uuid: uuid
+    - name: scoring_engine_name
+    - description: scoring_engine_description
+    - links: links
+
+**Example JSON representation of a Scoring Engine:**
+
+.. literalinclude:: samples/scoring_engine-list-response.json
+   :language: javascript
+
+List Scoring Engine Detailed
+============================
+
+.. rest_method::  GET /v1/scoring_engines/detail
+
+Returns a list of Scoring Engine resources with complete details.
+
+Normal response codes: 200
+
+Error codes: 400,401
+
+Request
+-------
+
+.. rest_parameters:: parameters.yaml
+
+   - limit: limit
+   - sort_dir: sort_dir
+   - sort_key: sort_key
+
+Response
+--------
+
+.. rest_parameters:: parameters.yaml
+
+    - uuid: uuid
+    - name: scoring_engine_name
+    - description: scoring_engine_description
+    - metainfo: scoring_engine_metainfo
+    - links: links
+
+**Example JSON representation of a Scoring Engine:**
+
+.. literalinclude:: samples/scoring_engine-list-detailed-response.json
+   :language: javascript
+
+Show Scoring Engine
+===================
+
+.. rest_method::  GET /v1/scoring_engines/{scoring_engine_ident}
+
+Shows details for a Scoring Engine resource.
+
+Normal response codes: 200
+
+Error codes: 404
+
+Request
+-------
+
+.. rest_parameters:: parameters.yaml
+
+   - scoring_engine_ident: scoring_engine_ident
+
+Response
+--------
+
+.. rest_parameters:: parameters.yaml
+
+    - uuid: uuid
+    - name: scoring_engine_name
+    - description: scoring_engine_description
+    - metainfo: scoring_engine_metainfo
+    - links: links
+
+**Example JSON representation of a Scoring Engine:**
+
+.. literalinclude:: samples/scoring_engine-show-response.json
+   :language: javascript