Rework the admin index page

[tdewolff]

The admin panel index should be clear and concise. It should display:

• (usage) information about the site
• errors of the last 4 weeks
• disk usage bar with % of disk space used by various components: assets, cache, logs, themes, modules, templates, database, core
• various maintanance functionality (or should this be on another page?) such as: empty logs, empty cache, minify and crush js/css/images, publish site

The console for Optimize site should be put in a fancybox popup. This would be used in future for updates and installing modules/themes/templates through our repository as well.

[s-p-n]

Sounds good to me. I think we can fit all of that onto the main index for the admin page- especially if you move the console into a fancybox. Sounds great.