Projects should be required to have a unique name

[rosieyohannan]

Currently it is possible to have multiple projects with exactly the same name, this makes searching and keeping track of projects difficult.

[pwaller]

Some thoughts:

• We need a plan for how to deal with pre-existing collisions.
• Ideally it should be enforced by the database. That will help in avoiding a TOCTOU bug.

[rosieyohannan]

reco v0.7.0

[rosieyohannan]

Here's some words for the error message:

You have already created a project with this name, please try again with a unique name. For a list of your existing projects, please run reco project list.