feat: add client_create.py script

+ blacken changed files
+ add client_create.py to readme
+ don't create admin client automatically

Creating a default client the user hasn't asked for could
create problems with unused clients building up big queues
5 jobs for 31-fix-error-running-without-any-clients-defined in 2 minutes and 37 seconds (queued for 7 seconds)
Status Job ID Name Coverage
  Ci Lint
passed #452704
shell
ci_lint

00:00:02

 
  Lint
passed #452705
docker
lint

00:00:34

 
  Build
passed #452706
shell
build

00:01:19

 
  Test
passed #452707
shell
test

00:00:34

 
  Release
passed #452708
shell
release

00:00:07