Check page speed for each new PR

[denar90]

I propose to run page speed for checking each new PR.
Purpose of running it with localhost, that new PR don't have to be merged to check page speed.
We are currently implementing this approach for marionettejs.com - marionettejs/marionettejs.com#486
The effort of this is insurance that newly PR is not downgrading page speed for site. I wrote small module - https://github.com/denar90/psi-ngrok, which helps run psi locally. Hence either it or some another approach can be used.

[FadySamirSadek]

@denar90 I like the idea a lot and will work on implementing it, I am also thinking about making a full audit on each PR and give it a lighthouse score so we can understand more how the change made affected the app. Thank you so much for sharing this 🙂