ready2go: Mapper-level icons and encouragement messages

[nrotstan]

Note: this feature has been implemented, but not yet submitted as a PR

• Add a trophy icon to both the top-nav and the user profile page that represents the user's mapper level (bronze, silver, and gold)

• Add messages to both the user profile page and home page (above the Start Mapping button) encouraging advanced users to validate, and other users to keep up the good work

Here is the full list of (english) messages, based on mapper-level progress

• You're on your way to becoming an intermediate mapper!
• You're over halfway to becoming an intermediate mapper!
• You've almost reached intermediate mapper!
• You've made intermediate mapper, keep it up!
• You're on your way to becoming an advanced mapper!
• You're over halfway to becoming an advanced mapper!
• You've almost reached advanced mapper!
• You're an advanced mapper! Next learn how to validate! [if never validated]
• Keep up the validation! We need experts like you to help! [if has validated]