[Generator::Plist] Ensure a CFBundleVersion is set for resource bundles

Pass the OTHER_CODE_SIGN_FLAGS variable (aka "Other Code Signing Flags")
to codesign, as Xcode does.

[WIP][PodTargetInstaller] Fix build dir for resource bundles

It was recursively defined before, which led to the target build product being scoped one level to deep.

Brings a unit test target with a simple test for checking if a storyboard
specified in the podspec is available at runtime.

Instead of CONFIGURATION_BUILD_DIR

Sort Dir.glob result in PathList case insensitively

Update for the removal of Pod::SourcesManager