💡 option in cloudflared service install to not start cloudflared

**Describe the feature you'd like**
When using `cloudflared service install`, `cloudflared` also attempts to start the start the service (equivalent to `systemd enable --now [service]`. For our use case, where we are provisioning devices its faster to not have to wait for cloudflared to come up (and also we see some transient errors where a timeout can happen and fail the entire process.

**Describe alternatives you've considered**
We could installed the systemd service ourselves, but I think this option would benefit others and also ensure our unit files are always up to date.

Start at the implementation of `cloudflared service install` and inspect how the service is started after installation, along with any existing service-install tests. Done means an option can install and enable the service without starting `cloudflared`, while the current default behavior remains unchanged.

Written by the indexing model from the issue text.