Challenges can have multiple flags

[KNOXDEV]

Rather than having multiple challenges to represent multiple parts, can we have single challenges that have multiple flags? I think that would address a lot of usability and transparency issues.

Basically, the flow chart would work like this:

1. if the challenge's flags can be obtained in any order, have one challenge with multiple flags.
2. if one challenge is long and difficult, have one challenge with multiple flags, where flags are given as you progress.
3. if the two challenges are in a particular order but could be split up into two different challenges without too much overlap, do so.