Minor doc edits, update UI guide images (#1219)

Author: javiermtorres

docs/assets/ui_guide_steps/datasets_page.png

@@ -0,0 +1,15 @@
+Settings API
+============
+
+Many APIs require some sort of secret or token to be able to work on them. They are usually stored in
+environment variables in personal use, like `OPENAI_API_KEY` or `MISTRAL_API_KEY`.
+
+For added security, the Lumigator API allows the user to store secrets as encoded values in its database,
+which will be used in requests but will not be returned in the API.
+
+Endpoints
+---------
+
+.. openapi:: ../specs/openapi.json
+   :include:
+     /api/v1/settings/*