Global: move standard_* directories to mkexp/*, experiments to types

CHANGES.rst

doc/mkexp.fodt

expconfig.py

mkexp

test.py

test/legacy/standard_environments/DEFAULT.config

test/legacy/standard_experiments/DEFAULT.config

test/legacy/standard_experiments/namelist.tmpl

test/legacy/standard_options/option1.config

test/legacy/test0001.config

test/legacy/test0001.run.tmpl

test/mkexp/DEFAULT.config

test/mkexp/environments/DEFAULT.config

test/mkexp/options/option1.config

test/mkexp/types/namelist.tmpl