It throws off Firefox and isn't being used

Summary:
The browser has them in the cache already, so we avoid loading it ourselves,
also we might not even have access to the icons from our context.
Some browsers (Opera does) set the favIconUrl of the tab to the base64 data
already, which is convenient. The base64 URL gets decoded in the krunner
plugin and if it fails or is not available, the browser icon is shown.
If the tab is audible or incognito, that icon is preferred.

Test Plan: Installed in Opera 40, Vivaldi 1.91 and Firefox 52, favicons appear in krunner.

Reviewers: #plasma, broulik, davidedmundson

Subscribers: plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D6717

This ensure media controls also work for players in an embedded <iframe>

Avoid cluttering the history with technical stuff.

Run cmake with -DINSTALL_CHROME_EXTENSION=ON if you want to install the provided
extension.crx file locally instead of having Chrome download it from the store.

Default is off where it will download the newest version from the store.

Added the public key for the key chrome created and this should be the final app ID

While they're pretty cool and look gorgeous they can break websites in interesting ways.
I personally would trade Breeze scrollbars over weird sizing issues anytime but I don't think
the CSS has the quality needed for being enabled by default.

Mostly stolen from some Gnome code and re-done by Kai.
CMake rewrite and FF support from me.