docs: part 1 - fix warnings in documentation generation (#2861)

**Description**
This PR removes some of the warnings when uv builds the docs
- Errors appear when generating docs about .md files not appearing in
toctree. ~~Adding content to the `providers-gen.py ` file that adds `---
orphan: true ---` to to each file.~~. Added a toctree generator to the
`providers-gen.py` file, this gets rid of the errors in the builds.
- Deletes the `_openai_compat` files, extension of PR #2849
- Adds the `files` APIs section to the `providers` toctree on the index
page
- Manually adds the `--- orphan: true ---` to the advanced apis. Ill try
to find a way to modify the providers code gen so it automatically adds
it, but this fixes the errors.
- Adds the `testing.md` to the `contributing` toctree
- Adds `starting_llama_stack_server.md` to `distributions` toctree

There are some other warnings im still looking at but this PR gets rid
of most of the toctree errors
Theres also an issue with the actual distribution-codegen that I can
investigate in another PR. Opened a bug for it here #2873

docs/source/providers/index.md

@@ -1,4 +1,4 @@
-# API Providers Overview
+# API Providers
 
 The goal of Llama Stack is to build an ecosystem where users can easily swap out different implementations for the same API. Examples for these include:
 - LLM inference providers (e.g., Meta Reference, Ollama, Fireworks, Together, AWS Bedrock, Groq, Cerebras, SambaNova, vLLM, OpenAI, Anthropic, Gemini, WatsonX, etc.),
@@ -12,81 +12,17 @@ Providers come in two flavors:
 
 Importantly, Llama Stack always strives to provide at least one fully inline provider for each API so you can iterate on a fully featured environment locally.
 
-## External Providers
-Llama Stack supports external providers that live outside of the main codebase. This allows you to create and maintain your own providers independently.
-
-```{toctree}
-:maxdepth: 1
-
-external.md
-```
-
-```{include} openai.md
-:start-after: ## OpenAI API Compatibility
-```
-
-## Inference
-Runs inference with an LLM.
-
 ```{toctree}
 :maxdepth: 1
 
+external
+openai
 inference/index
-```
-
-## Agents
-Run multi-step agentic workflows with LLMs with tool usage, memory (RAG), etc.
-
-```{toctree}
-:maxdepth: 1
-
 agents/index
-```
-
-## DatasetIO
-Interfaces with datasets and data loaders.
-
-```{toctree}
-:maxdepth: 1
-
 datasetio/index
-```
-
-## Safety
-Applies safety policies to the output at a Systems (not only model) level.
-
-```{toctree}
-:maxdepth: 1
-
 safety/index
-```
-
-## Telemetry
-Collects telemetry data from the system.
-
-```{toctree}
-:maxdepth: 1
-
 telemetry/index
-```
-
-## Vector IO
-
-Vector IO refers to operations on vector databases, such as adding documents, searching, and deleting documents.
-Vector IO plays a crucial role in [Retreival Augmented Generation (RAG)](../..//building_applications/rag), where the vector
-io and database are used to store and retrieve documents for retrieval.
-
-```{toctree}
-:maxdepth: 1
-
 vector_io/index
-```
-
-## Tool Runtime
-Is associated with the ToolGroup resources.
-
-```{toctree}
-:maxdepth: 1
-
 tool_runtime/index
-```
+files/index
+```