Refine static and shared library rules

[aherrmann]

Related to #15.
See ziglang/zig#19753 for further context.
Take Bazel's cc_shared_library rule as reference.

• Clearly distinguish between link time and build time dependencies, i.e. archives or shared libraries that need to be linked against whenever the zig_*_library target is used, and object or archive dependencies that need to be bundled into the output of the zig_*_library target.