Add more stuff in the side menu

[teolemon]

Problem

• Too many clicks to access stuff I find valuable
• Add more stuff in the side menu (it's scrollable vertically anyway)
• Add: My Prices, My Proofs, Settings, A specific Scan button (leads to search), Stats

Currently

Anonymous	Logged in

Todo

• [x] add Dashboard link (if logged in)
• [x] move "Add a price" above "Latest prices"
• [x] add Stats link
• [x] add About link ?