Analyze and resolve issues caused by `strict_warnings` toolchain feature from `score_bazel_cpp_toolchains`

[4og]

The score_bazel_cpp_toolchains toolchain has introduced a "strict_warnings" toolchain feature, which enables a very "strict" set of compile warnings.

Many Bazel targets in this repo explicitly set the "strict_warnings" feature, commonly in combination with "treat_warnings_as_errors" (see for example: https://github.com/eclipse-score/baselibs/blob/v0.2.3/score/bitmanipulation/BUILD#L23).

As a result, most targets either fail to compile or emit a large number of compiler warnings. Currently, this is being worked around by explicitly disabling the strict_warnings feature in .bazelrc (https://github.com/eclipse-score/baselibs/blob/v0.2.3/.bazelrc#L26).

Note: Users of the baselibs module may also need a similar workaround.

Task:

• Analyze which compiler warnings in the strict_warnings list should be removed if they are not beneficial.
• Identify which warnings/issues should instead be corrected in the baselibs source code.
• Propose changes to either the toolchain's strict_warnings feature or to the code in baselibs as appropriate.