Suggest: remove extra dev port(4507)

[Ahuigo]

I think there is no need to listen extra dev port(4507). The reasons are as follows:

1. Port 4507 may be occupied by other process.
2. It's hard to run multile examples via deno task dev.
3. If we run deno test example/*/server.test.ts, it's to heavy to open/close a listen port 4507.

If possible, I would like to submit this PR

[Craig Doremus]

At one point I thought that there was an environmental variable that optionally set the development port which would allow the running of different Ultra instances on the same machine.

[Ahuigo]

At one point I thought that there was an environmental variable that optionally set the development port which would allow the running of different Ultra instances on the same machine.

Not a same thing.

There are two ports:

1. The app port, default 8000.
2. The ultra development port, default 4507(Only when ULTRA_MODE=development)

I don't think it's necessary to take up two ports for either development or unit testing(e.g. cd examples/basic && deno test -A).

Ultra can fully share one port with App(default 8000)