refactor: Restructure project for single import

[Peetee06]

This PR restructures the project to align with official Flutter recommendations.

Using the package now requires only a single import:

import 'package:stomp_dart_client/stomp_dart_client.dart';

This makes working with stomp_dart_client.dart a little bit easier, because one can use things like VSCode code actions to automatically add an import to the package.

One note:
I couldn't run the tests in stomp_test.dart locally, because the spawnHybridCode method doesn't use the project's .dart_tool folder but rather a global one. The global one does not have the necessary packages installed, which is why the hybrid code can't be run. I couldn't find a way to fix this other than installing the necessary packages globally, which I don't want to do.

Please let me know if any further adjustments are desired. I'll be happy to fine-tune this PR further.

[KammererTob]

Thanks for the PR, i will have a look in the next few days.

[KammererTob]

@Peetee06 I tried to run the tests locally, but i ran into some issues. Maybe you have guidance for this:
In stomp_config_test.dart i do this: await platform.connect(config..resetSession());.

This currently throws the following error:

test/stomp_config_test.dart:23:34:
Error: The argument type 'StompConfig/*1*/' can't be assigned to the parameter type 'StompConfig/*2*/'.
 - 'StompConfig/*1*/' is from 'package:stomp_dart_client/src/stomp_config.dart' ('lib/src/stomp_config.dart').
 - 'StompConfig/*2*/' is from 'lib/src/stomp_config.dart'.
          await platform.connect(config..resetSession());
                                 ^
Error: Compilation failed.

If i try to use relative path for imports VSC complains (probably rightly so), that the path is not supposed to be relative.

Can't use a relative path to import a library in 'lib'.
Try fixing the relative path or changing the import to a 'package:' import.dart avoid_relative_lib_imports

Do you happen to know what to do with unit-tests?
Thanks!

[Peetee06]

@KammererTob, thanks for reporting this. It seems like dart couldn't see, that _connect_io.dart imports the same StompConfig. I fixed the import and the test succeeds locally now. Let me know if they succeed for you as well.

[KammererTob]

I have added a comment to one file, but this affects all files with hybrid tests. Can you please adjust those? For me they threw an error while testing.

Overall this is a breaking change, right? So i guess this would land in 2.0 then.

Thanks!

[Peetee06]

@KammererTob true, this is a breaking change. Thank you for reviewing!

[KammererTob]

Thank you. Looks good now. I will wait a few weeks if anything else comes up for a new release. I will release this as 2.0.0 then.

[Peetee06]

Very nice! Thank you for creating this project! Happy that I got to contribute!