How to deal with different CMOR tables from different projects about esmvaltool

[jvegreg]

The cmor checker can use CMIP5 or CMIP6 style CMOR tables. It has the CMIP5 and CMIP6 tables embedded into ESMValTool as submodules, but is also capable of reading CMOR tables from custom locations.

As long as we have an option in the namelist to specify the path to the tables and the projects provide CMOR tables in compatible formats, it should be easy to manage.

Also, it will be possible (and not very difficult) to add other formats for specifying variable requirements, but this is something I would try to avoid.

[mattiarighi]

This could be realized automatically as long as the project class (CMIP5 or CMIP6) is specified in the configuration file. For other classes, like OBS, obs4mips, EMAC, etc., I would also avoid defining additional formats, but I would stick to either CMIP5 or CMIP6.

[mattiarighi]

This has been solved by PR195.