Replace Spectron with Playwright or other

[FrancescoBorzi]

Is your feature request related to a problem? Please describe.

Spectron is going to be deprecated, see electron-userland/spectron#1045 and electron-userland/spectron#896

Describe the solution you'd like

We should replace it with another solution which is actively maintained

Describe alternatives you've considered

In the GitHub discussions above, several users suggested Playwright as an alternative and gave positive feedback about it.

https://playwright.dev/docs/api/class-electronapplication/

[maximegris]

Indeed Playwright seems to be a good fit and promising.

I will try to replace Spectron and also upgrade to Electron 15 during this weekend.

[maximegris]

Playwright is now used as end-to-end test runner.
It is a simple integration of Playwright wich may need to be improved in future commit.

I also upgraded the project to Electron 15.