Passing in HA_PORT doesn't work, as $PORT isn't being passed in correctly in code

The current logic that implements passing in `$HA_PORT` from the `docker run` isn't properly making it to `dmgcmd.exe` due to this line of code:
``` PowerShell
$PORT = $HA_PORT -or "8060"
Start-Process $DmgcmdPath -Wait -ArgumentList "-EnableRemoteAccess"
```
I think [`-or`](https://docs.microsoft.com/en-us/powershell/module/microsoft.powershell.core/about/about_logical_operators?view=powershell-7.1#long-description) is being incorrectly used here. By this logic, `$PORT` always evaluates to `True` (rather than picking up 8060 if no `$HA_PORT` is passed in - I think the intention here was to perform [NULL Coalesce](https://stackoverflow.com/questions/10623907/null-coalescing-in-powershell)?)

So you get this error every time:

``` Text
The value of port is invalid. Please set an integer bigger than or equal to 0 and less than or equal to 65535.
```
Since the expression turns out to be `.\dmgcmd.exe -EnableRemoteAccess TRUE`.

**Possible Solution**