gitlab-ci: employ GIT_SUBMODULE_STRATEGY: recursive

9 jobs for ci in 6 minutes and 35 seconds (queued for 4 seconds)
Status Job ID Name Coverage
  Build
passed #74177
docker linux amd64
build:linux:amd64

00:03:09

passed #35857
docker linux amd64
build:linux:amd64

00:01:22

canceled #72970
amd64 linux docker
build:linux:amd64

canceled #73212
amd64 linux docker
build:linux:amd64

passed #73346
amd64 linux docker
build:linux:amd64

00:04:07

 
  Test
canceled #73296
amd64 linux docker
deckard:linux:amd64

passed #35860
docker linux amd64
respdiff:linux:amd64

00:02:29

passed #35858
docker linux amd64
test:linux:amd64

00:00:56

passed #35859
docker linux amd64
deckard:linux:amd64

00:03:57