Update source structure to follow fortran template

• documentation page
• command line interface:
  • set namelist file name and working directory: edk -n edk.nml path/to/cwd
  • get help message (edk -h) and version info (edk -v)
• added folder with compile scripts: scripts/
• new checking scripts for check cases (run in CI)
• added second check case with variogram fitting
• added version files version.txt and version_date.txt
• use FORCES as dependency
• move lonely routines to the modules where they are used
• renamed modules to unique naming scheme: mo_edk_*
• function tVar now returns real(dp) instead of real(8)