R6G2 Changes

• prepare_ecmwf.sh adjusted for R6G2
• First processing steps
• Update aggregation script
  • COSMO-REA6/R6G2: add agg_1hrTOmonMin_2D, agg_1hrTOdayMin_2D, agg_1hrPt_3Dheight functions
  • R6G2: update variables to be processed and adding loadbalancing options
• Exemplarily adding 3D height variable (wind speed 100m) incl zaxisdes
• Updating conf