chore: Create initial release process scripts for official ASF source release

[andygrove]

Which issue does this PR close?

Part of https://github.com/apache/datafusion-comet/issues/394

Rationale for this change

We need to establish the basic ASF release process

What changes are included in this PR?

• Copy create-tarball, release-tarball, verify-release-candidate scripts from DataFusion and modify them for Comet
• Change the crate name from comet to datafusion-comet (comet was taken, and I have reserved datafusion-comet in crates.io)
• Add placeholder README

How are these changes tested?

They are not tested yet. I will test them prior to our first release.