Move low-level routines from cell_methods.F into cell_types.F

git-svn-id: svn://svn.code.sf.net/p/cp2k/code/trunk@14432 bac0169d-1eea-4375-b5f6-f89d2ced9994
Move get_particle_set() from particle_types.F into particle_methods.F

git-svn-id: svn://svn.code.sf.net/p/cp2k/code/trunk@14433 bac0169d-1eea-4375-b5f6-f89d2ced9994