Remove the simulation language interpreter SLI #456

Job	Run time
copyright_headers	19s
clang-format	15s
black	39s
cppcheck	6m 32s
flake8	21s
forbidden_types	13s
isort	23s
lychee_IGNORED	25s
mypy	47s
pydocstyle	15s
pylint	35s
rstcheck	45s
unused_names	13s
vale	42s
sphinx-rtd	2m 21s
sphinx-conda	0s
build_macos (macos-latest, clang, openmp, mpi, python, gsl, ltdl, boost, hdf5, optimize, warning)	4m 1s
build_linux (ubuntu-20.04, gcc, boost, optimize, warning)	12m 29s
build_linux (ubuntu-20.04, gcc, openmp, python, gsl, ltdl, boost, optimize, warning)	26m 5s
build_linux (ubuntu-20.04, gcc, mpi, python, gsl, ltdl, boost, optimize, warning)	6h 0m 14s
build_linux (ubuntu-20.04, gcc, openmp, mpi, python, gsl, ltdl, boost, hdf5, sionlib, libneurosim...	6h 0m 15s
	12h 57m 49s

Provide feedback