packaging: first cut at debian packaging through CI and publishing to
MergeTB Debian package server.

coding standards: first pass at conformance to MergeTB coding standards

config: the config system for gobble now has the following semantics

1. read the configuration file (by default /etc/gobble.yml but
overridable with a flag)
2. fill in any missing configuration with default values
3. override any config file values or default values with user provided
flag values

with this new system, gobbel even tries to figure out what it's
interface should be, so installing from a debian package with zero user
intervention may work in some situations. currently we just pick the
first interface, but in the future we may inspect the neighbor tables to
look for routers and pick based on that.

Signed-off-by: Ryan Goodfellow <rgoodfel@isi.edu>