* [CI] Migrate to rockylinux8 / manylinux_2_28_x86_64
* Scrub all references to CentOS 7
* Fix
* Remove use of yum
* Use gcc-10 in cpu
* Temporarily disable -Werror
* Use GCC 9 for now
* Roll back gRPC
* Scrub all references to manylinux2014_x86_64
* Revise rename_whl.py to handle no-op rename
* Change JDK_VERSION back to 8
* Reviewer's comment
* Use GCC 10
* Use Spark 3.5.1, same as in pom.xml
* Fix JAR install
* Create pyproject.toml
* Implement a custom build backend (see below) in packager directory. Build logic from setup.py has been refactored and migrated into the new backend.
* Tested: pip wheel . (build wheel), python -m build --sdist . (source distribution)
