Add/wrap performance testing/extended debug commands that are Sauce specific

[christian-bromann]

The DevTools team has created a bunch of WebDriver extensions over the last year that might worth being added to the driver in various of languages. In WebdriverIO I already added these commands:

https://github.com/webdriverio/webdriverio/blob/master/packages/wdio-protocols/protocols/saucelabs.json

The document should be self describing but it would be cool if users could call those commands directly instead of using the JS Executor workaround.

[nadvolod]

@christian-bromann awesome suggestion 👍 I started something similar a few months back but we decided to hold off for the Alpha and Beta versions. But likely will be released for v1.0. Are you thinking something like this or this? Just to make sure we're on the same page.

[christian-bromann]

Are you thinking something like this

No, what I thinking of here is to extend the Selenium client with these sauce specific commands so that someone can call e.g. driver.throttleNetwork('Regular #F')

[nadvolod]

@christian-bromann cool, so basically performance-related stuff as I can tell from the doc?

[christian-bromann]

@nadvolod yes, these commands are mainly performance/extended debugging related