📖 Consolidate Metal3 Contributing guide in community repo

CONTRIBUTING.md

@@ -1,39 +1,12 @@
-# How to Contribute
+# How to Contribute to Ironic Standalone Operator
 
-Metal3 projects are [Apache 2.0 licensed](LICENSE) and accept contributions via
-GitHub pull requests.
+> **Note**: Please read the [common Metal3 contributing guidelines](https://github.com/metal3-io/community/blob/main/CONTRIBUTING.md)
+> first.
 
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-- [Certificate of Origin](#certificate-of-origin)
-   - [Git commit Sign-off](#git-commit-sign-off)
-
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-## Certificate of Origin
-
-By contributing to this project you agree to the Developer Certificate of
-Origin (DCO). This document was created by the Linux Kernel community and is a
-simple statement that you, as a contributor, have the legal right to make the
-contribution. See the [DCO](DCO) file for details.
-
-### Git commit Sign-off
-
-Commit message should contain signed off section with full name and email. For example:
-
- ```text
-  Signed-off-by: John Doe <[email protected]>
- ```
-
-When making commits, include the `-s` flag and `Signed-off-by` section will be
-automatically added to your commit message. If you want GPG signing too, add
-the `-S` flag alongside `-s`.
-
-```bash
-  # Signing off commit
-  git commit -s
-
-  # Signing off commit and also additional signing with GPG
-  git commit -s -S
-```
+<!-- Add repo-specific sections here as needed -->
+<!-- For example: versioning policies, release processes, etc. -->