LHCBGAUSS-815 SuperChic2

Porting the merge of branch 'LHCBGAUSS-815.SuperChic2'

See merge request !94 (merged) for 'Sim09'

(cherry picked from commit 972a8296)

da5809e5 version 2.03 of SuperChic
6a771e36 updated to version 2.04 of SuperChic
fa826f14 fixed status codes and temporarily added example dec files
604c403f updated CMakeLists for SuperChic2
db455534 Fix use of SuperChic2 internal headers
92074620 Update CMakeLists.txt to remove unnecessary fortran flag
c68212e8 Removed files which create duplicate symbols.
aa61c1e2 Modified LHA for updated Pythia.
7f5c22b5 Fixed the setEvent for current version of Pythia.
20450618 Moved 'include' to 'common', updated SuperChic2 generation script, and remvoed decfile examples.