Update to support python 3.13

[jannast]

Updated gprc versions to support python 3.13

• gRPC version from 1.60.1 to 1.70.0 (JAVA_GRPC_VERSION, PYTHON_GRPC_VERSION)
• protoc version from 4.25.0 to 5.29.4 (PYTHON_PROTOC_VERSION)
• com.google.protobuf version from 0.9.1 to 0.9.6

Checklist

The following aspects have been respected by the author of this pull request, confirmed by both pull request assignee and reviewer:

• Changelog update (necessity checked and entry added or not added respectively)
  • Pull Request Assignee
  • Reviewer
• README update (necessity checked and entry added or not added respectively)
  • Pull Request Assignee
  • Reviewer

[a-kleinf]

this version has known issues: see Release v1.70.0
would suggest to use a newer version. This will need the change of the used python version in build-python.yml to at least python 3.9 (in my opinion it should be 3.13). Python 3.8 support is then dropped, which is actually fine for me.
Also the version of the packages for python have to match a package version used with java.

[maximilianpilz]

It is necessary to add integration tests accross languages (and potentially versions) first, e.g. Java client and Python server and vice versa, and afterwards the Python and Java versions can be made to differ, i.e. instead of using a common version the version declarations will be split up.
Otherwise the intention of this pull request can not be reasonably implemented.