Comply with DITA - Using Hammer - xrefs

[Lennonka]

What changes are you introducing?

Converting xrefs to path based in Using Hammer guide

Why are you introducing these changes? (Explanation, links to references, issues, etc.)

DITA compliance

Anything else to add? (Considerations, potential downsides, alternative solutions you have explored, etc.)

• Please, stick with the scope of the changes in this PR when reviewing.

Contributor checklists

• I am okay with my commits getting squashed when you merge this PR.
• I am familiar with the contributing guidelines.

Please cherry-pick my commits into:

• Foreman 3.16/Katello 4.18 (Satellite 6.18)
• Foreman 3.15/Katello 4.17
• Foreman 3.14/Katello 4.16 (Satellite 6.17; orcharhino 7.4)
• Foreman 3.13/Katello 4.15 (EL9 only)
• Foreman 3.12/Katello 4.14 (Satellite 6.16; orcharhino 7.2 on EL9 only; orcharhino 7.3)
• Foreman 3.11/Katello 4.13 (orcharhino 6.11 on EL8 only; orcharhino 7.0 on EL8+EL9; orcharhino 7.1 with Leapp)
• Foreman 3.10/Katello 4.12
• Foreman 3.9/Katello 4.11 (Satellite 6.15; orcharhino 6.8/6.9/6.10)
• We do not accept PRs for Foreman older than 3.9.

[github-actions]

The PR preview for 42d9cb7 is available at theforeman-foreman-documentation-preview-pr-4274.surge.sh

No diff compared to the current base

show diff

[maximiliankolb]

diff LGTM.