Added ProtocolBuffers

[stemann]

Currently, there is protoc_jll, which provides the protobuf compiler, protoc, and the libprotobuf, and libprotobuf-lite run-time libraries (in shared library form), but not the static run-time libraries - and the versioning got a bit off course, cf. #9796.

Since

Protobuf C++ disclaims all cross-runtime support and requires an exact match between its generated code version and its runtime version at all times.

it is very much preferable to link with libprotobuf statically, and not dynamically. Cf. https://protobuf.dev/support/cross-version-runtime-guarantee/#cpp

In Yggdrasil, there are packages that have protoc_jll as a HostBuildDependency, but there are also packages that need the run-time libraries and have protoc_jll as a Dependency.

The present PR accomplishes the following goals:

• Separate (and correct) versioning of
  • the protobuf project, and protoc compiler, e.g., v28.2, (in JLL: ProtocolBuffersCompiler),
  • and the C++ runtime library, e.g., v5.28.2 (in JLLs ProtocolBuffers, and ProtocolBuffersSDK)
• Static libraries (in JLL: ProtocolBuffersSDK), cf. recommendation from https://github.com/onnx/onnx/blob/v1.17.0/README.md#linux
• Shared libraries (without protoc) in JLL ProtocolBuffers.

Over time, these packages could replace protoc_jll.

[stemann]

Temporarily also added ProtocolBuffersCompiler - this should likely depend on ProtocolBuffers (protoc depends on the C++ runtime library libprotobuf), and be built in a separate step.

[stemann]

One could also consider adding ProtocolBuffersLite with just libprotobuf-lite, but the protobuf CMake system does not support building just libprotobuf-lite out-of-the-box (and so it is likely entangled in the generated Cmake/Pkg-config)