Introduce login via device flow

[f1ames]

This PR adds device flow as auth method to VSC extension.

I kept "Token" auth method as well, but we can remove/hide it if needed.

Also the VSC "pop-up" is a bit ugly, but I haven't found better way really. Plain notification which is shown in bottom, right corner may be easily missed.

It still uses dev API which is a reason for error visible on the end.

Changes

• Added ability to choose login method when running Monokle: Login command, Device flow or Token.
  • It uses @monokle/synchronizer package internally.
• Reworked the code and removed what was extracted to core package.

Fixes

• None.

Remarks

• Testing is still a bit cumbersome, due to a fact that tests are run in separate VSC instance (special package designed for testing). So there is no direct access to plugin code. I tried exposing some objects (like RuntimeContext) as public API to be accessible but it seems not to work correctly (it only allowed me to expose simple values and objects, all functions and classes were not for some reason...). So I went with stubbing with env vars like https://github.com/kubeshop/vscode-monokle/pull/25/files#diff-02936d84b2bfa566af0a5cc8f21ea3a4bfb12099c6d4b406c2cd1f189237e947R2 and https://github.com/kubeshop/vscode-monokle/pull/25/files#diff-efc97f3d7f5ea73b6a8c0688705131d6440b0370a7d91bda46884b4f068a0d2cR2. Not perfect but seems enough for now. Later, either we can change it or preprocess the code for production to remove those dev only block.

Checklist

• [x] tested locally
• [ ] added new dependencies
• [ ] updated the docs
• [x] ~added~updated a test

[f1ames]

@WitoDelnat please take a look. It should be enough to switch URLs when device flow is integrated with rest of the Cloud envs.