Update access rules docs for GA modernized access rules editor

[brambrink]

As discussed, from 10.20.0 the modernized entity access rules editor will be made GA and enabled by default. The old editor will be deprecated from 10.20.0 as well and removed from 11.0.0.
This PR updates the docs for this and default the modernized access rules editor.

[MarkvanMents]

@brambrink
I have just been told that we put out #8992 because the GA has been delayed until 10.24. Is this the case?
We can leave this open and relabel it for 10.24. If you still think it is GA in 10.20 then you might need to talk to @jdiehl ?

[brambrink]

@brambrink I have just been told that we put out #8992 because the GA has been delayed until 10.24. Is this the case? We can leave this open and relabel it for 10.24. If you still think it is GA in 10.20 then you might need to talk to @jdiehl ?

Hey Mark, that's correct, we decided this during refinement this morning and did not have time yet to inform you here. I will leave this PR here for now and update it when we make the modernized editor GA if that's okay.

[MarkvanMents]

Thanks for the confirmation.
I've labeled this for 10.24 and switched it to draft to indicate that there is work required.
I'll wait to hear from you nearer the time to update the PR for the release.