MPI-ESM: adjusted post processing scripts with respect to the CH4 variables

- aggregation / diag / cmor-rewrite:
  + fixed/added CH4 variable processing where necessary
  + moved decadal chunk definition from mapping to run scripts
- runpp: added decadal chunk definition and definition of input/forcing files used for the aggregation part
- cmor_ctl/test_*: updated CH4 simulation submission scripts
- cdocmorinfo: Updated attributes - references will have to be adjusted using NCO because of CMOR max string length limitations
- tables: updated / added CH4 variable mapping info
- conf: preliminary configuration to be adjusted after feedback of TK