/etc/default/homebridge not escaped properly on Ubuntu
**Describe The Bug:**
The default file (```/etc/default/homebridge```) created when running ```hb-service install``` on Ubuntu doesn't properly escape the variable ```HOMEBRIDGE_OPTS```

**To Reproduce:**
```sh
$ cat /etc/default/homebridge 
HOMEBRIDGE_OPTS=-I -U "/var/lib/homebridge"
UIX_STORAGE_PATH="/var/lib/homebridge"

# To enable web terminals via homebridge-config-ui-x uncomment the following line
HOMEBRIDGE_CONFIG_UI_TERMINAL=1

DISABLE_OPENCOLLECTIVE=true
```

**Expected behavior:**
```sh
HOMEBRIDGE_OPTS="-I -U \"/var/lib/homebridge\""
```

**Environment:**

* **Node.js Version**: v14.15.3
* **NPM Version**: 6.14.9
* **Homebridge Version**: 1.1.7
* **Operating System**: Ubuntu
* **Process Supervisor**: Systemd 

