Persistent docker session

[SmartManoj]

Solves #1811

Set PERSIST_SESSION=1 and SSH_PASSWORD

[rbren]

This is really neat!

I wonder if there's a reasonable way to make this the default behavior. We'd have to pick a port and hard-code a secret...

[SmartManoj]

#847 (review)

If one has access, they still can access it via the front end.

---

Port: 63710

d: 6 (similar to the shape of 'd')
e: 3 (common leetspeak substitution)
v: 7 (similar to the shape of 'v')
i: 1 (common leetspeak substitution)
n: 0 (commonly used for 'n' in leetspeak)

[rbren]

Thanks @SmartManoj!