docs(deploy-key): run as standard user
docs(add-host): add description, param and sample
docs(add-channel): add description, param and sample
style(typo):
docs(list-hosts): add missing param info
docs(screenshot): add new screenshot (auto-generated)
docs(mk): add and fix tasks' documentation
style(stdout): improve formatting and coherence
refactor(mk,deploy-service): remove command related to systemd
fix(service,mk): solve No directory, logging in with HOME=/

closed #27
feat(doc): add 'doc' task to generate screenshots
fix(service): check lock directory existence
style(service): use bash syntax
style(service): format stdout message