Update documentation and version history for 2.3.0

- Populate 2.3.0 release notes in docs/source/version_history.rst covering all new features, API changes, and bug fixes since 2.2.0 with contributor credits.
- Overhaul docs/source/installation.rst for 2.3.0: document Abseil, GoogleTest, Google Benchmark, and cuDSS dependencies, submodule workflow, WITH_* CMake options, Config-mode dependency discovery, Bzlmod Bazel build, and 2.3 migration notes; modernize CMake CLI invocations and consolidate build-tree export guidance.
- Document CUDA_SPARSE (cuDSS) in docs/source/nnls_solving.rst.
- Update tutorial code snippets and solver summaries in docs/source/nnls_tutorial.rst and docs/source/gradient_tutorial.rst for Abseil logging and 2.3.0.
- Add abseil_cpp dependency to package.xml.
- Fix broken and redirected external URLs across docs/source/*.rst.

Change-Id: I1a356c4ffe4a91d4384816c4e7a83d1cc4566346