Moved all doctests to new doc/tests

actions/doc/index_dev.rst

core/doc/helper.rst

core/doc/pm3argparse.rst

doc/gettingstarted.rst

doc/tests/CMakeLists.txt

doc/tests/data/1AKI.pdb

doc/tests/data/1AKIA.hhm

doc/tests/data/1CRN.pdb

doc/tests/data/1CRNA.hhm

doc/tests/data/structure_db_small.dat

doc/tests/scripts/core_file_checks.py

doc/tests/scripts/core_msg_error.py

doc/tests/scripts/core_pm3argparse.py

doc/tests/scripts/hello_world.py

doc/tests/scripts/loop_backbone.py

doc/tests/scripts/loop_frag_db.py

doc/tests/scripts/loop_fragger.py

doc/tests/scripts/loop_main.py

doc/tests/scripts/loop_monte_carlo.py

doc/tests/scripts/loop_structure_db.py