Allow AlmanacHost blueprints to build a meaningful CommandInterface

Summary: Ref T9253. Provide a meaningful command interface for Almanac hosts.

Test Plan:
Configued and leased a real host (sbuild001.phacility.net) and ran a command on it.

$ ./bin/drydock command --lease 90 -- ls /
bin
boot
core
dev
etc
home
initrd.img
lib
lib64
lost+found
media
mnt
opt
proc
root
run
sbin
srv
sys
tmp
usr
var
vmlinuz

Reviewers: chad, hach-que

Reviewed By: chad, hach-que

Maniphest Tasks: T9253

Differential Revision: https://secure.phabricator.com/D14126