Update license

[apinnick]

• Updated the site license to CC BY-SA 4.0.
• Updated only the year on the Red Hat license because d/s docs still refers to CC BY-SA 3.0. If this changes, I will update the RH license file.

Closes #885

• I am familiar with the contributing guidelines.

Please cherry-pick my commits into:

• Foreman 3.10/Katello 4.12
• Foreman 3.9/Katello 4.11 (planned Satellite 6.15)
• Foreman 3.8/Katello 4.10
• Foreman 3.7/Katello 4.9 (Satellite 6.14)
• Foreman 3.6/Katello 4.8
• Foreman 3.5/Katello 4.7 (Satellite 6.13; orcharhino 6.6/6.7)
• Foreman 3.4/Katello 4.6 (EL8 only)
• Foreman 3.3/Katello 4.5 on EL7 & EL8 (Satellite 6.12 on EL8 only; orcharhino 6.4/6.5 on EL8 only)
• We do not accept PRs for Foreman older than 3.3.

[github-actions]

The PR preview for cfda104 is available at theforeman-foreman-documentation-preview-pr-2915.surge.sh

The following output files are affected by this PR:

show diff

show diff as HTML

[ekohl]

I had a look at the authors. First of all, I've taken the time to update the mailmap: #2921

With that you can easily retrieve the various authors: git log --pretty='format:%aN <%aE>' web | sort -u. That identifies b397c04 as a commit by @lumarel while all others are done by Red Hatters or @maximiliankolb.

I think technically we should get approval from @lumarel to change the license.

As for the guides themselves, the list is a bit longer. Due to privacy I'll work with @apinnick offline to come up with a plan instead copy-pasting all names here.

[lumarel]

@ekohl it speaks very vividly for the project to even ask about such in my eyes small license changes!
Thank you for asking, and yes of course I approve 👍🏻

[maximiliankolb]

I am OK with changing the license from "CC BY-SA 3.0" to "CC BY-SA 4.0" for my contributions.

I would like to see more people review/ACK this change.

[Lennonka]

LGTM

[ekohl]

As discussed, we don't cherry pick this to stable branches.