fix(ghdl): Improve usability and auto-add osvvm libs to project

This MR adds the following changes:

• in GHDL target, the code previously iterated over all the simulation top modules set in SimTop; however, only the last ones' dependencies were considered. This, depending on the order of the modules in SimTop and the actual dependencies, could easily lead to ghdl compilation failures. Now all the SimTop module's dependencies are considered and added to CMakeList.txt properly
• in GHDL target, an unused source file added to the project used to lead to compilation failures; the unused module (whose dependencies GHDL will not resolve realizing this is not in the dependency tree) still ended up in CMakeList.txt without dependencies, and GHDL wanted (but failed) to compile this when the project is build for simulation
• FWK used to add only stuff under ::fwfwk::src namespace to project, thus OSVVM sources did not end up there. Now setSources and doOnCreate is also done for ::fwfwk::lib.