Add combined premixing workflows for Run 3#27753

Merged

cmsbuild merged 4 commits intocms-sw:masterfrom makortel:premixRun3

Aug 23, 2019

+37-15

Commits on Aug 12, 2019

Commits on Aug 14, 2019

Increase the input file step number by 1 for Nano step in upgrade-style combined premixing workflows
makortel
committed

Commits on Aug 16, 2019

Define stage2 premixing workflows for all datasets (for given years)
makortel
committed