Applications is unresponsive if request timeout fails

[bhermann]

Describe the bug
When the request to the web server takes too long, the CLI just dumps the Future Timeout Exception and does not get shut down properly.

Exception in thread "main" java.util.concurrent.TimeoutException: Futures timed out after [10 seconds]
	at scala.concurrent.impl.Promise$DefaultPromise.ready(Promise.scala:255)
	at scala.concurrent.impl.Promise$DefaultPromise.result(Promise.scala:259)
	at scala.concurrent.Await$.$anonfun$result$1(package.scala:215)
	at scala.concurrent.BlockContext$DefaultBlockContext$.blockOn(BlockContext.scala:53)
	at scala.concurrent.Await$.result(package.scala:142)
	at de.upb.cs.swt.delphi.cli.commands.SearchCommand$.execute(SearchCommand.scala:61)
	at de.upb.cs.swt.delphi.cli.DelphiCLI$.delayedEndpoint$de$upb$cs$swt$delphi$cli$DelphiCLI$1(DelphiCLI.scala:78)
	at de.upb.cs.swt.delphi.cli.DelphiCLI$delayedInit$body.apply(DelphiCLI.scala:31)
	at scala.Function0.apply$mcV$sp(Function0.scala:34)
	at scala.Function0.apply$mcV$sp$(Function0.scala:34)
	at scala.runtime.AbstractFunction0.apply$mcV$sp(AbstractFunction0.scala:12)
	at scala.App.$anonfun$main$1$adapted(App.scala:76)
	at scala.collection.immutable.List.foreach(List.scala:389)
	at scala.App.main(App.scala:76)
	at scala.App.main$(App.scala:74)
	at de.upb.cs.swt.delphi.cli.DelphiCLI$.main(DelphiCLI.scala:31)
	at de.upb.cs.swt.delphi.cli.DelphiCLI.main(DelphiCLI.scala)

To Reproduce
Steps to reproduce the behavior:

1. Produce a query that takes over 10s (e.g. setting limit to 10000)
2. Observe

Expected behavior
A nice error message should be given and the client should be terminated.

Screenshots
n/a

Affected components (if known)
cli

Desktop (please complete the following information, if relevant):
n/a

Smartphone (please complete the following information, if relevant):
n/a

Additional context
n/a

[bhermann]

Fixed with #30