Add ability to filter out Recommended extensions and provide a UI for it

In term of features:

• Home page should display recommended extensions with a button to see all extensions
• Remember what the user was browsing (recommended or full list) when navigating to an extension so that the user clicks in the breadcrumb to go back to the home page (or if he navigates back there), what is displayed corresponds to what he was looking at
• Ability to turn on/off the Recommended view on home page
• Ability to define a page defining what Recommended means
• When viewing a extension the user should see quite visibly whether the extension is recommended or not

See attached screenshots for ideas.