Feature Request: Expose API to connect/disconnect client

[AngellusMortis]

So currently you have to use the GameRCON as a context manager to connect/disconnect to a server:

client = GameRCON('host', 'port', 'password', timeout=10)
async with client as pot_client:
    response = await pot_client.send('your_command')
    print(response)

If you want to manage this yourself (connection pooling), you have to call __aenter__ and __aexit__ directly which does not feel very clean. It would be nice of the contents of both are moved to a stable connect/disconnect API method so you can manage the connect yourself instead of faking the context manager:

client = GameRCON('host', 'port', 'password', timeout=10)
await client.connect()
try:
    response = await pot_client.send('your_command')
    print(response)
finally:
    await client.disconnect()

Example use case:

You have multiple servers running and you want to do a rolling restart of them and then notify users of the status as they restart. Very rough code that probably does not even work:

servers = [(ip, port, password), (ip, port, password), (ip, port, password)...]
clients = [GameRCON(ip, port, password) for ip, port, password in servers]

try:
    await asyncio.gather(*[await c.connect() for c in clients])
    await asyncio.gather(*[await c.send("Broadcast Test") for c in clients])
finally:
    await asyncio.gather(*[await c.disconnect() for c in clients])