Feature/logins

Adds some inputs in the page and compare creation modals for cookies, as well as a cookies field in the database, enabling scylla to pass cookies to charybdis and capture screenshots behind logins.
The 2000 here is what we call a 'magic number'.  it's difficult to know what 2000 represents... is it the pixel offset? Does it represent time? MS, Seconds... is it a max time, or a min time?

So we should put 2000 in a variable that effectively labels it:
```
var snapshotTimeoutInMS = 2000;
```