fix(README): clarify for logs and correct for --tail option

[VincentCauchois]

• Clarify: split documentation of CLI logs for Docker services into three distinct parts

  • basic command to log all lines,
  • command with tail option to log only a certain number of lines from the end,
  • command to log lines for a specific service only

• Correct: --tail option, which works, rather than -n option which is not recognized