[RFC]: Move to a simpler model

[tmrts]

Instead of performing template life-cycle operations, encapsulate these operations

Example workflow

boilr render github:tmrts/boilr-license .

boilr render file:/home/tmrts/template .

Behind the scenes:

• Execution metadata recorded for usage with boilr template log or boilr list
• Template caching from github
• Removes template template download/save/delete/update/validate

Why?:

• Most workflows are similar, and users shouldn't have to write a couple of lines to get what they want
• Less mental overhead thanks to simplified template management

Why not?:

• Latency concerns due to cache invalidations and staleness checks
• Consistency concerns due to using a cache

[jdoklovic]

Just FYI, I'm working on some changes around this that I think will clean up the workflow a lot.
PR should be coming soon...