protobuf-java-28.3-160000.2.2

- python: switch to pypi package to get the cythonized component
- drop python-protobuf-setup_py.patch (obsolete)

- Add versionize-shlibs.patch, delete static-utf8-ranges.patch
  * Build the libutf8_range and libutf8_validity as shared library
    to conform to SLPP

- update to 28.3:
  * Fix packed reflection handling bug in edition 2023.
  * Mute the minor version warning
  * Populate Kotlin Manifest Files
  * Re-export includingDefaultValueFields in deprecated state for
    important Cloud customer. (https://github.com/protocolbuffers
    /protobuf/commit/3b62d78dc70d2b43af5998d427452246279363c7)
  * Cherrypick restoration of mutableCopy helpers (https://github
    .com/protocolbuffers/protobuf/commit/3ea568a9b6107ebf0d617c47
    6f53a31490fd3182)
  * Mute the minor version warning

- Added patch: static-utf8-ranges.patch
  * Build the libutf8_range and libutf8_validity as static library
    to avoid installcheck failures

- Java: fix generating proper maven descriptor for protoc on aarch64
- Java: rename global variable buildarch -> protoc_arch to avoid
  name clash on sle15

- Java: mimic the bazel build and build also the protobuf-javalite
  artifact

- Python: keep building for 15.4+

- Java: add maven artifact metadata for the protoc binary
  * make the main package archful, since the protoc artifact
    metadata declares the architecture of the binary

- Python: Generate the headers that the Cython native library needs
  to build
- Added patch:
  * python-protobuf-setup_py.patch
    + make the bitrotten setup.py find the source files for the
    C native library
    + Modify the code so that the build works on python 3.6 too

- Splitting the java and python parts into separate packages
  * allows much more readable and simple spec files
  * allows disabling bindings separately from the main package
- Build protobuf-java with the upstream version that is currently
  4.28.2
- Add a pre_checkin.sh script to synchronize the changes files