fix_snmp hard-coded community "public" and sent its config-mode line
through _send_command, which waits for the exec prompt: in config mode
it ran into its timeout and left the session there (#6).
netgear_smart implements napalm-device-types 4.13's configure_snmp_agent
steps: community (read-only), contact and location from the caller
through _apply_config_lines, which waits for any prompt and reports a
refused line; config mode is left in all cases; the configuration is
saved and the community checked in show snmp. v7 firmware, which has
no SNMP commands in its CLI, says so. A value that would break the CLI
is refused.
napalm-device-types is now declared in pyproject.toml and
requirements.txt (#7).
BREAKING CHANGE: run_device_action is removed.
Closes#6. Part of #7 and #8.
