sys-perf: Call infrastructure_provisioning.py instead of infrastructure_provisioning.sh

In etc/system_perf.yml and etc/longevity.yml, call infrastructure_provisioning.py instead of infrastructure_provisioning.sh.

Note that as part of this ticket there's also an opportunity to simplify/shorten those files. Instead of each step being their own function like "prepare environment", "infrastructure provisioning" etc... It should be possible to have only one or a few sections to deploy the cluster and run the test, and analyze step needs to remain a separate function.

Example (sketch):

functions:

  "prepare environment":

     # maybe leave as is

  "deploy cluster and run tests":

    - command: shell.exec

      params:

          working_dir: work

          script: |

              set -e

              set -v

              source dsienv.sh

              virtualenv ./venv

              infrastructure_provisioning.py

              mongodb_setup.py

              run_test.py

              make_artifact.sh # (possibly could rather go into analyze, to be discussed)