ClimaLand should not use pkgdir for output

[Sbozzolo]

The experiments in ClimaLand use pkgdir to determine their output path. This is not a good idea. In geenral, pkgdir will be a subfolder in .julia and there is no reason to save output files in such a hard-to-find place. Second, pkgdir depends on how the package is installed, so it will lead to different results for the same simulation.