docs: refresh testing_integration.rst (#53338)
docs: refresh testing_integration.rst (#53338)

* docs: refresh testing_integration.rst

Ensures the examples can be run:
- fedora25 is not available anymore, use fedora29 instead
- the posix/ci alias does not exist anymore, use shippable/posix/ instead
- explain how to list the target without argcomplete

* ansible-test should be in $PATH
* call ansible-runner from bin/, not test/runner
* we don't use credentials.template anymore, we use a collection of .template files.
* low-case bash bc we refresh to name of the binary
* refresh the command of Windows-CI example
* Update docs/docsite/rst/dev_guide/testing_integration.rst

Co-Authored-By: goneri <b6a5d0fb34e23aaca974165ba33111041cac4264@lebouder.net>

thaim/ansible,thaim/ansible