Add `w3up profiles` method to list profiles

[dchoi27]

Is your feature request related to a problem? Please describe.
Right now there's no way to list the profiles you've created, making it inconvenient to fish them out if you've forgotten them

Describe the solution you'd like
A CLI method to list the profiles

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Additional context
Add any other context or screenshots about the feature request here.

[ice-breaker-tg]

Note to self:

This is a little complicated with the CONF module we are using, as there is no reference to profiles outside of the files themselves.

Think about a way to do this in a sane manner.

[ice-breaker-tg]

Maybe create a "index/manifest" config file that can be loaded along side the main profile config, allowing cli/etc to know what other profiles exist.