pin to aes_fix branch (micromdm#454)

Resolves micromdm#453

This is a temporary fix until the proper CBC variant for content encryption is implemented in pkcs7

dependency update

Update everything to latest and cleans up unused dependencies.

user management

reset used io.Reader for pkg upload (micromdm#209)

update readme

refactor package main (micromdm#49)

move the contents of main.go into app package.
scaffold a CLI subcommands package. 
add a version package and add /_version handler to print detailed version info.

add dependencies for scpe/bolt (micromdm#48)

bump version

update readme and dockerfile