Protected cookies list: Add a column to display if a cookie still exists or not

[Yvon TANGUY]

There is no easy way to know if a cookie still exists for all protected cookies.
Some protected cookies may have expires, and have been deleted automatically by Mozilla. This is a normal behavior.

The idea is to add a column, in the protected cookie list (within the preferences dialog) to know for each protected cookies, if the cookie still exists.
An icon may also be added eventually before the domain name.