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

[andygrove]

Which issue does this PR close?

Part of #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.

[andygrove]

There is already a comet crate, so I renamed this. I have reserved the crate: https://crates.io/crates/datafusion-comet

[andygrove]

@snmvaughan @parthchandra please review when you have the time

[viirya]

Hmm, I think this is for publishing cargo package. But I think Comet should be released as a maven package at maven repository? So users can simply add Comet as a dependency in their pom file?

[andygrove]

Hmm, I think this is for publishing cargo package. But I think Comet should be released as a maven package at maven repository? So users can simply add Comet as a dependency in their pom file?

It depends whether we want to allow other Rust projects to be able to use the Spark-compatible expressions that we are implementing, outside of the Comet/Spark integration.

The maven release will be needed for sure.

[andygrove]

Hmm, I think this is for publishing cargo package. But I think Comet should be released as a maven package at maven repository? So users can simply add Comet as a dependency in their pom file?

Also, regardless of whether we choose to publish the crate or not, I think it is better to not use the name of an existing crate, and good to have the author information be consistent with other DataFusion crates.