stdout/stderr around
A lot of functions in the cmd and ctl packages were passing these
around and barely using them. Replaced them with a logger for most
functions. Some functions get an io.Writer instead so that their
tests can find the output they're looking for.
More cleanup on fb-1766: reworked the tests that were using io.Pipe
or os.Pipe to check their results so they now use a bytes.Buffer.
Unexported some variables that didn't need to be exported.
Fixed NewConfigCommand to use the provided stderr, not os.Stderr.
Added tests for rbf_dump, rbf_page, and keygen, since those weren't
being tested at all.
Added chksum_test, final cleanup.
(cherry picked from commit f627199acb)
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.
