🌱 Perform minimal structural improvements

[abrugaro]

Performed minimal structural improvements for the repository that include:

• Renamed LaunchVSCodePage class and launchVSCode method to better reflect the current behaviour
• Added quotes to installExtensionFromVSIX method to support path with whitespaces
• Added test script to the packages.json file
• Removed the explicit call to the close method as Playwright automatically closes the app once all the tests are finished
• Disabled the fully parallel execution of tests since the two tests of the file depends on the first test opening VSCode (parallelization is still enabled for different files)
• Added output folders, .env file and node_modules to the .gitignore
• Other minor improvements