Write a blog post for the new site launch and include contribution instructions

[alan707]

• blog post for launch
• contribution guidelines and instructions for folks that want to help
• blog post should be a call to action for people to help find bugs and fix them with the provided instructions.

[alan707]

@fweikert to share a draft for review. @kapunahelewong will land bazelbuild/bazel#29499 for contribution guidelines to be linked.

[fweikert]

Blog post draft: https://docs.google.com/document/d/1kR2S8f19aGZoHqbTTpkx88XmG5stVOQzpbYWVyuQDxM/edit?usp=sharing