[GNU FSDG] Extensions that work explicitly with Chromium web browser.

The following packages are dedicated for integration of various Ubuntu related services (eg. Unity WebApps, Ubuntu Online Accounts etc.) with Chromium web browser.

[1] unity-chromium-extension
[2] webaccounts-chromium-extension
[3] unity-scope-chromiumbookmarks
[4] webaccounts-extension-common
As GNU Project has discontinued/abandoned distributing Chromium web browser for historic reasons, these extensions should be removed from the software repository to comply with GNU FSDG.