Allows for depots with non-default stream depths

[thejustinwalsh]

Fix for issue #12.

• It may not be idiomatic rust.
• The logic could likely be simplified, as the stream name without the depot prefixed is not emitted from the function.
• Tests ensure it works like it used to while supporting bespoke stream depth setups.

[thejustinwalsh]

Added logic to migrate any existing projects that are using a non-defaul stream depth.

[parnic-sks]

🚀 👍

[thejustinwalsh]

While this appears to make the DB entries look correct, it did not work once I did a test deployment.
I might need @jorgenpt's help on this one.