Display detailed information for installed packages

[albertinad]

• current state (installed, missing, extraneous as it is right now)
• home page
• keywords
• dependencies list
• available versions to update/install

[shaneparsons]

You've probably already thought of this, but it would be nice if clicking the new version icon could link to a changelog or the plugin's github page, just so we know if it's worth updating or not.

[albertinad]

Included in #55