Planned for 4.0: Add a better CLI & remove web UI

[linc]

There's a few challenges in Porter:

• Timeouts when using the web interface
• Keeping the CLI & web interfaces in sync limits both
• The web interface doesn't give feedback until it's finished

It turns out the answer to all 3 is the same: Get rid of the web interface and improve the CLI instead. So, in version 4.0, we'll be doing just that. I think there will be quite a few benefits, including:

• Always have real-time feedback.
• Easier debugging and improved error reporting.
• More standardized command structure.
• Making it easier to add new packages.

Previously, there were a couple reasons to maintain web support:

• Lack of access to CLI on Windows.
• A lower hurdle for non-power users to interact with the product.

Over time, the first reason went away (Windows has good CLI support now) and the second kinda turned out to be a lie. Porter is very much a "prosumer" product that requires at least some engineering knowledge. Otherwise, you're going to ask someone else to run it for you, and that person would most appreciate better CLI support.

As Porter continues to evolve and mature, it's important to keep focusing on what makes it the easiest to use and maintain. This prospective change certainly clears that hurdle.

Hat tip to @tobyzerner for the suggestion.

[linc]

Note this was implmented in #36 and went into 3.4 because I'm a bit lackadaisical with versioning / lost track of what I'd released as the year wore on.