Added features for auto updating and pruning vagrant box images

[Stromweld]

Signed-off-by: Corey Hemminger hemminger@hotmail.com

Description

Added features for auto updating vagrant box images to latest and auto pruning specific box images

Check List

• [ ] All tests pass. See TESTING.md for details.
• [ ] New functionality includes testing.
• [ ] New functionality has been documented in the README if applicable.

[tas50]

I've meant to do this for a LONG time since we release boxes all the time.

[Stromweld]

Yeah I've meant to get to it for a long time too. Thanks for the merge.