Plugin support for project weblinks

Plugins can now contribute project links that will be displayed on the
project list screen in the 'Repository Browser' column.

Change-Id: Ia96679b249dd9677d9138e8af6239e1e5ea6f1d4
Merge "Plugin support for project weblinks"
Remove unnecessary @SuppressWarnings("unchecked")

Change-Id: Iaa36d80464504d482783a200e895d12d2c073a6f