Add BUILD_ID to /etc/os-release

[anthonydahanne]

Describe the Enhancement

Add BUILD_ID to /etc/os-release: today there's no information as to when the image was built.

Possible Solution

The BUILD_ID field could be used to add the date of build; I believe that would be enough to distinguish between different Jammy stacks

Motivation

For example, if you build the same stack several times (22.04 for example), you won't be able to figure out which 22.04 your users were using when you start investigating asking them to send their /etc/os-release

[anthonydahanne]

additional context: https://www.freedesktop.org/software/systemd/man/os-release.html