Add basic support and tests for Ubuntu 24.04 LTS

[raulillo82]

See #5543 as a reference:

• Bootstrap repo data
• Define bootstrap repo URL
• Adapt bootstrap SLS files
• Add repos to spacewalk-common-channels.ini

Tracked in: https://github.com/SUSE/spacewalk/issues/23880

[mayrstefan]

Additional challenges:

1. sources must be specified in deb822 format and placed in /etc/apt/sources.list.d
2. if the source is not gpg signed apt shows a notice. This will change to a warning with 24.10

deb822 is supported since apt version 1.1. Current versions of apt

OS	apt version
Debian 11	2.2.4
Debian 12	2.6.1
Ubuntu 22.04	2.4.11
Ubuntu 23.04	2.6.0
Ubuntu 23.10	2.7.3
Ubuntu 24.04	2.7.12

So maybe it would be a good choice to use apt version >= 2.7.12 as a condition to switch the format

Source: https://discourse.ubuntu.com/t/spec-apt-deb822-sources-by-default/29333

[mayrstefan]

Any updates or is there already a timeline? Ubuntu 24.04 will be released next week.

Also necessary

• Uyuni-Client-Tools for Ubuntu 24.04

[mayrstefan]

Ubuntu 24.04 LTS has been released