Lack of randomness in pset template GlobalIds

The GlobalIds used in the distributed pset template definitions are not very unique. Here's a sample:

```
'3trzS0qRmHuO00025QrE$V'
'087P_0qXaHuO00025QrE$V'
'0h76K0qS4HuO00025QrE$V'
'0xpDi0qS4HuO00025QrE$V'
'1UNlG0qS4HuO00025QrE$V'
'3hy1C0qSGHuO00025QrE$V'
'1tQQG0qSKHuO00025QrE$V'
'2u_ay0qSKHuO00025QrE$V'
'073rA0qSOHuO00025QrE$V'
'1xexg0qU4HuO00025QrE$V'
'3_B7e0qU4HuO00025QrE$V'
'1cp2I0qUiHuO00025QrE$V'
'2YQUq0qV4HuO00025QrE$V'
'3AP4i0qWSHuO00025QrE$V'
'2Vni80qWWHuO00025QrE$V'
```

Is this a problem? Should it be fixed? Ping @berlotti @TLiebich @aothms