Change network/web color icons to consistent style

Summary: The old style didn't match the sharp, grid aligned style of most Breeze icons and there was some inconsistency between network/web related color icons that used globes. Also changed applications-internet into a symlink to preferences-system-network since it was a duplicate of the same icon.

Test Plan:
preferences-system-network and preferences-web-browser-*

internet-web-browser

Reviewers: VDG, ngraham

Reviewed By: VDG, ngraham

Subscribers: abetts, ngraham, kde-frameworks-devel

Tags: Frameworks

Differential Revision: https://phabricator.kde.org/D17496