Implement anonymous Telemetry (self-hosted instances stats)

[Matt0550]

Implement a anonymous telemetry system able to:

• Track self-hosted instances sessions
• Check for updates (new version dropped)
• Track errors
• Commands stats

Privacy related:

• Do not track chat_id, username, user_id or other P.I.I.
• Opt-out from telemetry using ENV var
• Update readme and add a privacy policy