Interactive AA installer

[seanlinsley]

Since Rails generators have the ability to pause and prompt the user for input, we should be using it to smooth over common configuration issues that people run into. This ticket will be used to keep track of and discuss new features. Here's the list so far:

• choosing the class name for the user & whether or not to use an existing class
• creating an install without authentication
• display warning if require_tree detected in application.css or application.js
• default user credentials configuration -> Isn't the default user a security risk? #3457 replaced by Proposal to remove the default user #3988

[javierjulio]

Some good ideas here. I'll leave this open if someone wants to tackle it. I think the most we should do for the require_tree issue is just display a warning if we detect it in either file. Otherwise its working as intended since its meant to include everything. Its just not practical to ever use require_tree since order is very important in both types. I'm afraid we are overthinking this and a simple warning is sufficient.