[modules] Add a header files that builds now.
[modules] Add a module for Vc.
[modules] Extract out TException. The module build setup of Exception is still not well understood.
[modules] Do not duplicate TClassEdit.h. Move ESTLType.h in the same module.
[modules] Disable the Exception module until we can sort out the issue.
[modules] Move TTreeIndex and TChainIndex in separate modules. This avoids pulling-in the tree module.
[modules] Hide ctor-local enum.
[modules] Split part of proof in separate modules in order to build its dictionary.
[modules] Rename 'Local Global' gFile because it clashes with gFile macro def in TFile.h
[modules] Move MessageTypes.h in a separate module. This way we avoid its users to pull entire core_base.
[modules] graf3d_g3d requires c++.
[modules] Move rsa-specific C headers in a dedicated module.
[modules] Add requested but missing forward declaration.
[modules] linux macro is not seen, when compiling with -fmodules.
[modules] Move the ESysConstants in Rtypes. It breaks the modularization otherwise.
[modules] Disable building some dictionaries with modules.

The reason is that the dictionaries are walking close to the edge and beyond when
it comes to the standard. Sometimes they rely on not using template instantiations
until the end of the TU, which breaks when modules are on.
[modules] Update progress with building ROOT with modules on.
[modules] Move NetErrors in separate module. It is cross referenced.
[modules] Document current issues and comment out the module minuit and matrix.
[modules] Move AuthConst in separate module because it is cross refed.