revert to old gridder interface (almost)

9 jobs for PowerGrid in 7 minutes and 59 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build Docker
passed #864212
build_docker_from_cache

00:00:14

 
  Test
passed #864214
test_mpi

00:04:11

passed #864213
test_serial

00:04:50

80.0%
 
  Demo Runs
passed #864219
run_bernoulli

00:00:25

passed #864220
run_curve_fitting

00:00:23

passed #864216
run_getting_started_1

00:00:29

passed #864217
run_getting_started_2

00:01:07

passed #864218
run_getting_started_3

00:02:54

passed #864215
run_ipynb

00:01:22