restart services on change, fix some idempotency issues

this does quite a few things:

• executor and salad are now restarted if the config for them is changed
  • ansible salad stops/starts executor when it restarts salad
• pip install is not idempotent so that is worked around
• wireguard is now restarted on config change, and all config for it is now in the wireguard role
• check for restarting minio_configure was broken, so it was simplified to be consistent with other service restart handlers
• setting the minio root password was not idempotent, which meant that it was replaced on every invocation of ansible on the target gateway. this broke subsequent runs of minio_configure (e.g. if it is restarted by ansible) because the credentials it used to configure minio initially were lost/replaced