unix socket support

[kone-tlammi]

Support for binding Quart to unix sockets without appending port.

This already somewhat works

import quart
app = quart.Quart("foo")
@app.route("/")
def hello():
    return "hello\n"

app.run("unix:///tmp/bar.sock")

but the port number is appended to the socket name so the server will listen in /tmp/bar.sock:5000:

$ curl --unix-socket /tmp/bar.sock\:5000 http://_/
hello

[pgjones]

Use Hypercorn directly for this, see docs