Add Contributing Section and Update CONTRIBUTING.md Link (#604)

* Update READ.ME

Add #contributing section and update the correct contribute URL.

* Remove 'Guidelines' link from the 'Contributing' section

I have removed the hyperlink and reference to 'Guidelines' in the README.md file. This change was made because the 'How to Contribute' and 'Guidelines' links led to the same information, creating redundancy.

* Update contribution link from markdown to website

- Changed the contribution guide link in the README.md from the markdown file to the corresponding section on the official website.
- This change ensures that the link remains stable and is not impacted by the frequent changes to Markdown files.

Author: ZeeJJ123

README.md

@@ -51,6 +51,14 @@ The [project homepage](https://hugegraph.apache.org/docs/quickstart/) contains m
 
 hugegraph-toolchain is licensed under `Apache 2.0` License.
 
+## Contributing
+
+- Welcome to contribute to HugeGraph, please see [How to Contribute](https://hugegraph.apache.org/docs/contribution-guidelines/contribute/) for more information.
+- Note: It's recommended to use [GitHub Desktop](https://desktop.github.com/) to greatly simplify the PR and commit process.
+- Thank you to all the people who already contributed to HugeGraph!
+
+[![contributors graph](https://contrib.rocks/image?repo=apache/hugegraph-toolchain)](https://github.com/apache/incubator-hugegraph-toolchain/graphs/contributors)
+
 ### Contact Us
 
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