qtdesigner.path - Handle relative paths from workspace or venv

[Guts]

Qt Designer is now often used within the PyQt5-tools package (as you say into your readme) and it could be great to allow relative paths for the pyqt-integration.qtdesigner.path (and others):

• from the ${workspaceFolder}
• or from the python.pythonPath

[mine2chow]

Usually they are using PyQt5-tools or python distribution like Anaconda, if the command "designer" is available in your system, you can set it to pyqt-integration.qtdesigner.path and it should work.

If someone wants to put the PyQt5-tools package into ${workspaceFolder}, sounds interesting to add this support.

[Jaylee89]

if use Anaconda, you can configure it, it works for me.

<anaconda path>/bin/Designer.app/Contents/MacOS/Designer