* User: Add name and image URL
More personalization options, prerequisite for btcpayserver/app#3.
Additionally:
- Remove ambigious and read-only username from manage view.
- Improve email verification conditions and display.
- Greenfield: Update current user. Prerequisite for btcpayserver/app#13.
* Refactor UpdateCurrentUser
* Replace new columns by UserBlob
* Update email check and add test case for mailbox addresses
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Co-authored-by: nicolas.dorier <nicolas.dorier@gmail.com>