Process related to user approvement.

[AndrejLavrionovic]

By clicking approve button:

• User Access level should be changed
• Approve button must to be replaced by label, something like "Approved"
• Confirmation email must be sent to used - Done.

[AndrejLavrionovic]

When administrator pressing the Approve button:

• User Access level is changing on "REGISTERED" - Done.
• Approve button is replacing by "APPROVED" label - Done.
• Confirmation email is sending to user - Done.