pangolin --all-versions pollutes STDOUT with ANSI chars

[dpark01]

It seems that since the switch to pangolin v4, pangolin --all-versions now emits something like the following (as viewed via less):

[32m****;Pangolin running in usher mode.;****ESC[0m;pangolin: 4.0.3;pangolin-data: 1.2.133;constellations: v0.1.4

Whereas previously in pangolin v3, it was strictly a machine-parsable list of version numbers. Given that pangolin --all-versions is frequently parsed by wrapper scripts and pipelines and conveyed downstream in public health reporting, it would seem to me that both the ANSI coloring control characters, as well as the **** and "running in usher mode" message should perhaps be shuffled to STDERR or suppressed or otherwise removed from the STDOUT stream, which should be kept clean for machine parsing.

To be honest, "Pangolin running in XXX mode" is kind of an untrue statement for --all-versions anyway, since it isn't really running at all. Maybe removing this whole colored block is the right way to go?

[dpark01]

oops, dupe of #420