Fix visibility of kvs_cpp and kvsvalue

[jgetas]

When trying to build the C++ example following the description at examples/README.md as external module, I run into the issue:

[...]
ERROR: /home/.../persistency_test/BUILD:1:10: in cc_binary rule //:kvs_example: Visibility error:
target '@@score_persistency+//src/cpp/src:kvs_cpp' is not visible from
target '//:kvs_example'
Recommendation: modify the visibility declaration if you think the dependency is legitimate. For more info see https://bazel.build/concepts/visibility
[...]

The library must be publicly visible if an application wants to make use of it.

[github-actions]

License Check Results

🚀 The license check job ran with the Bazel command:

bazel run --lockfile_mode=error //:license-check

Status: ⚠️ Needs Review

Click to expand output

[License Check Output]
Extracting Bazel installation...
Starting local Bazel server (8.4.2) and connecting to it...
INFO: Invocation ID: c3f16b0d-dc74-464e-9138-8c30fe1f4d54
Computing main repo mapping: 
Computing main repo mapping: 
Computing main repo mapping: 
WARNING: For repository 'rules_python', the root module requires module version rules_python@1.4.1, but got rules_python@1.8.3 in the resolved dependency graph. Please update the version in your MODULE.bazel or set --check_direct_dependencies=off
WARNING: For repository 'score_rust_policies', the root module requires module version score_rust_policies@0.0.4, but got score_rust_policies@0.0.5 in the resolved dependency graph. Please update the version in your MODULE.bazel or set --check_direct_dependencies=off
WARNING: For repository 'rules_cc', the root module requires module version rules_cc@0.1.2, but got rules_cc@0.2.16 in the resolved dependency graph. Please update the version in your MODULE.bazel or set --check_direct_dependencies=off
WARNING: For repository 'googletest', the root module requires module version googletest@1.17.0.bcr.1, but got googletest@1.17.0.bcr.2 in the resolved dependency graph. Please update the version in your MODULE.bazel or set --check_direct_dependencies=off
WARNING: For repository 'google_benchmark', the root module requires module version google_benchmark@1.9.4, but got google_benchmark@1.9.5 in the resolved dependency graph. Please update the version in your MODULE.bazel or set --check_direct_dependencies=off
Computing main repo mapping: 
Computing main repo mapping: 
Loading: 
Loading: 3 packages loaded
Loading: 3 packages loaded
    currently loading: 
Loading: 3 packages loaded
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Loading: 3 packages loaded
    currently loading: 
Analyzing: target //:license-check (4 packages loaded, 0 targets configured)
Analyzing: target //:license-check (4 packages loaded, 0 targets configured)

Analyzing: target //:license-check (72 packages loaded, 10 targets configured)

Analyzing: target //:license-check (117 packages loaded, 208 targets configured)

Analyzing: target //:license-check (156 packages loaded, 2299 targets configured)

Analyzing: target //:license-check (163 packages loaded, 3448 targets configured)

Analyzing: target //:license-check (168 packages loaded, 3491 targets configured)

Analyzing: target //:license-check (168 packages loaded, 3497 targets configured)

Analyzing: target //:license-check (168 packages loaded, 3497 targets configured)

Analyzing: target //:license-check (172 packages loaded, 5510 targets configured)

Analyzing: target //:license-check (193 packages loaded, 5707 targets configured)
[10 / 17] Creating runfiles tree bazel-out/k8-opt-exec-ST-d57f47055a04/bin/external/score_tooling+/dash/tool/formatters/dash_format_converter.runfiles [for tool]; 0s local ... (3 actions, 2 running)
Analyzing: target //:license-check (199 packages loaded, 5722 targets configured)
[13 / 17] JavaToolchainCompileClasses external/rules_java+/toolchains/platformclasspath_classes; 0s disk-cache, processwrapper-sandbox ... (2 actions running)
INFO: From Generating Dash formatted dependency file ...:
INFO: Successfully converted 66 packages from Cargo.lock to bazel-out/k8-fastbuild/bin/formatted.txt
Analyzing: target //:license-check (199 packages loaded, 5722 targets configured)
[15 / 17] JavaToolchainCompileBootClasspath external/rules_java+/toolchains/platformclasspath.jar; 0s disk-cache, processwrapper-sandbox
Analyzing: target //:license-check (199 packages loaded, 5722 targets configured)
[16 / 17] [Prepa] Building license.check.license_check.jar ()
Analyzing: target //:license-check (199 packages loaded, 5722 targets configured)
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Analyzing: target //:license-check (200 packages loaded, 10056 targets configured)
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Analyzing: target //:license-check (200 packages loaded, 10056 targets configured)
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Analyzing: target //:license-check (200 packages loaded, 10056 targets configured)
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Analyzing: target //:license-check (200 packages loaded, 10056 targets configured)
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Analyzing: target //:license-check (200 packages loaded, 10056 targets configured)
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Analyzing: target //:license-check (200 packages loaded, 10056 targets configured)
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Analyzing: target //:license-check (200 packages loaded, 10056 targets configured)
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INFO: Analyzed target //:license-check (202 packages loaded, 10170 targets configured).
INFO: Found 1 target...
Target //:license.check.license_check up-to-date:
  bazel-bin/license.check.license_check
  bazel-bin/license.check.license_check.jar
INFO: Elapsed time: 41.409s, Critical Path: 4.23s
INFO: 17 processes: 12 internal, 4 processwrapper-sandbox, 1 worker.
INFO: Build completed successfully, 17 total actions
INFO: Running command line: bazel-bin/license.check.license_check ./formatted.txt <args omitted>
usage: org.eclipse.dash.licenses.cli.Main [-batch <int>] [-cd <url>]
       [-confidence <int>] [-ef <url>] [-excludeSources <sources>] [-help] [-lic
       <url>] [-project <shortname>] [-repo <url>] [-review] [-summary <file>]
       [-timeout <seconds>] [-token <token>]

[github-actions]

The created documentation from the pull request is available at: docu-html

[vinodreddy-g]

@jgetas could you rebase it and we can merge it.

[PandaeDo]

LGTM