Account/User entity

[vikiival]

We are slowly getting to the tipping point where we need to replace user as String! with UserEntity

Would would it do?:

• cache various metrics
• calculating scores
• Flips - what, price bought, price sold, date bought, date sold Users Activity - average sale ? Max sale Max flip

REF:

• https://github.com/kodadot/rubick/issues/52
• https://github.com/kodadot/magick/issues/19
• https://github.com/kodadot/rubick/pull/157