Chore: Remove the OS/package update feature from Jeedom.

[Mips2648]

Description

Remove the obsolete OS/package update feature:

• Python 2 is no longer supported,
• Python 3 package updates are becoming obsolete with Debian 12 and 13 (because they are managed in plugins venv),
• only APT updates remained available on DIY boxes, where users can and should manage them themselves so it does not make sense to keep it in the core.

I took the opportunity to also refactor the var declarations in update.js and replace them by let and const

Suggested changelog entry

• Breaking change: Remove the OS/package update feature from Jeedom (it was only available on DIY boxes)

Related issues/external references

Fixes https://community.jeedom.com/t/core-develop-deb13-retours/150813

Types of changes

• Bug fix (non-breaking change which fixes)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
  • This change is only breaking for integrators, not for external standards or end-users.
• Documentation improvement