This is the first in a series of PRs to enable `coder ssh` to replace
`coder vscodessh`.
This change adds `--network-info-dir` and `--network-info-interval`
flags to the `ssh` subcommand. These were formerly only available with
the `vscodessh` subcommand.
Subsequent PRs will add a `--ssh-host-prefix` flag to the ssh
subcommand, and adjust the log file naming to contain the parent PID.