[GR-63220] Make ModuleLayerFeature layer aware

[graalvmbot]

This PR makes the RuntimeModuleSupport and the ModuleLayerFeature layer aware.

The RuntimeModuleSupport is now an ApplicationLayerOnlyImageSingleton which stores the bootLayer of the final layer. To ensure all modules are visible, all the modules from the base layer are also included in the final bootLayer, using the SharedLayerBootLayerModulesSingleton.

To allow the runtime module access to work properly, the Module#openPackages and Module#exportedPackages are now only finalized in the application layer, using the relocatable constants (via the CrossLayerConstantRegistry). The field values of all layers are aggregated in the LayeredModuleSingleton. This allows to add opens or exports in extension layers.

This PR also adds support for future constants that have a null value in the application layer. Instead of an offset, the null value (0) is directly written.