The generate-config command was printing a fixed string rather than calling
NewConfig() which is the canonical source for default config. I also noticed
that we were depending on two different toml libraries, and so collapsed that to
a single one. We have to use pelletier rather than BurntSushi because the viper
library that we use depends on pelletier.
Renames `config` to `generate-config` and implements a new `config`
command that generates the configuration file based on the current
state instead of printing a static string.
