Make it easy for the browser tool to reuse sessions

[cjellick]

The browser tool is much more useful when it is reusing the user's sessions. You can control this now with a browsersettings.json file in the workspace, but thats not easy for the user to control...or know about.

Would be nice to expose the "headless" flag as well.

[cjellick]

Not sure how yet, so we'll have to talk it out first :-)

[g-linville]

Browser settings are now available when you click on your profile in the top right and go to the settings menu.

[sangee2004]

I am seeing lot of issues when testing the browser settings with build - 18eaca7d8d

Following issues are logged to track them:

#488
#489
#490