Added two developer guide and removed from README ' builder docker image' and 'launch service from source' (#2590)

### What problem does this PR solve?


### Type of change

- [x] Documentation Update

docs/references/CONTRIBUTING.md

@@ -1,52 +0,0 @@
----
-sidebar_position: 0
-slug: /contribution_guidelines
----
-
-# Contribution guidelines
-
-Thanks for wanting to contribute to RAGFlow. This document offers guidlines and major considerations for submitting your contributions. 
-
-- To report a bug, file a [GitHub issue](https://github.com/infiniflow/ragflow/issues/new/choose) with us.
-- For further questions, you can explore existing discussions or initiate a new one in [Discussions](https://github.com/orgs/infiniflow/discussions).
-
-
-## What you can contribute
-
-The list below mentions some contributions you can make, but it is not a complete list.
-
-- Proposing or implementing new features
-- Fixing a bug
-- Adding test cases or demos
-- Posting a blog or tutorial
-- Updates to existing documents, codes, or annotations.
-- Suggesting more user-friendly error codes
-
-## File a pull request (PR)
-
-### General workflow
-
-1. Fork our GitHub repository.
-2. Clone your fork to your local machine: 
-`git clone git@github.com:<yourname>/ragflow.git`
-3. Create a local branch: 
-`git checkout -b my-branch`
-4. Provide sufficient information in your commit message
-`git commit -m 'Provide sufficient info in your commit message'`
-5. Commit changes to your local branch, and push to GitHub: (include necessary commit message)
-`git push origin my-branch.`
-6. Submit a pull request for review.
-
-### Before filing a PR
-
-- Consider splitting a large PR into multiple smaller, standalone PRs to keep a traceable development history. 
-- Ensure that your PR addresses just one issue, or keep any unrelated changes small.
-- Add test cases when contributing new features. They demonstrate that your code functions correctly and protect against potential issues from future changes.
-### Describing your PR 
-
-- Ensure that your PR title is concise and clear, providing all the required information.
-- Refer to a corresponding GitHub issue in your PR description if applicable. 
-- Include sufficient design details for *breaking changes* or *API changes* in your description.
-
-### Reviewing & merging a PR
-- Ensure that your PR passes all Continuous Integration (CI) tests before merging it.

docs/references/_category_.json

@@ -1,8 +1,8 @@
 {
   "label": "References",
-  "position": 3,
+  "position": 4,
   "link": {
     "type": "generated-index",
-    "description": "RAGFlow References"
+    "description": "Miscellaneous References"
   }
 }