DOC: ITK_CONSTEXPR* and ITK_HAS_CXX11_RVREF are deprecated
DOC: ITK_CONSTEXPR* and ITK_HAS_CXX11_RVREF are deprecated

`ITK_CONSTEXPR_FUNC`, `ITK_CONSTEXPR_VAR` and `ITK_HAS_CXX11_RVREF` are
deprecated and documented as such. They are available for remote module
backward compatibility.

Change-Id: I651e0205a4299f9c18d71bdd8f0b26ac7fc51a3a

stnava/ITK,malaterre/ITK,malaterre/ITK,BRAINSia/ITK,fbudin69500/ITK,malaterre/ITK,fbudin69500/ITK,blowekamp/ITK,vfonov/ITK,fbudin69500/ITK,Kitware/ITK,spinicist/ITK,LucasGandel/ITK,Kitware/ITK,vfonov/ITK,spinicist/ITK,fbudin69500/ITK,thewtex/ITK,hjmjohnson/ITK,richardbeare/ITK,BRAINSia/ITK,InsightSoftwareConsortium/ITK,blowekamp/ITK,BRAINSia/ITK,BRAINSia/ITK,LucasGandel/ITK,InsightSoftwareConsortium/ITK,spinicist/ITK,hjmjohnson/ITK,vfonov/ITK,thewtex/ITK,fbudin69500/ITK,fbudin69500/ITK,richardbeare/ITK,malaterre/ITK,malaterre/ITK,blowekamp/ITK,spinicist/ITK,richardbeare/ITK,spinicist/ITK,Kitware/ITK,InsightSoftwareConsortium/ITK,stnava/ITK,blowekamp/ITK,LucasGandel/ITK,blowekamp/ITK,hjmjohnson/ITK,LucasGandel/ITK,fbudin69500/ITK,vfonov/ITK,malaterre/ITK,vfonov/ITK,blowekamp/ITK,Kitware/ITK,hjmjohnson/ITK,richardbeare/ITK,vfonov/ITK,stnava/ITK,vfonov/ITK,malaterre/ITK,InsightSoftwareConsortium/ITK,BRAINSia/ITK,spinicist/ITK,fbudin69500/ITK,stnava/ITK,blowekamp/ITK,thewtex/ITK,stnava/ITK,InsightSoftwareConsortium/ITK,thewtex/ITK,LucasGandel/ITK,vfonov/ITK,Kitware/ITK,malaterre/ITK,InsightSoftwareConsortium/ITK,stnava/ITK,spinicist/ITK,hjmjohnson/ITK,stnava/ITK,spinicist/ITK,thewtex/ITK,stnava/ITK,richardbeare/ITK,stnava/ITK,Kitware/ITK,vfonov/ITK,BRAINSia/ITK,thewtex/ITK,thewtex/ITK,Kitware/ITK,InsightSoftwareConsortium/ITK,spinicist/ITK,LucasGandel/ITK,blowekamp/ITK,LucasGandel/ITK,hjmjohnson/ITK,BRAINSia/ITK,malaterre/ITK,LucasGandel/ITK,richardbeare/ITK,richardbeare/ITK,hjmjohnson/ITK