Remove content_moderation.module BC layers

Hm, I spun out #3093132: Remove isLatestRevision, getLatestRevision, getLatestRevisionId from the ModerationInformation service and #3088748: Remove the deprecated views relationship provided by content moderation to the internal ContentModerationState entity type. I don't mind combining these if it's easier, but I would have imagined smaller issues would have been easier to commit.

I have looked into the two tickets mentioned and it looks good to me. But we still have some more deprecated methods which we need to remove.
Attached is the screenshot after applying the patches mentioned in #4.
Agree with @Sam152 smaller issues would be easier to commit.

> Agree with @Sam152 smaller issues would be easier to commit.

Looking at the parent, one issue per module/component seems to be better standard. Some are smaller but several are just as big or bigger. I think these removal only issues are pretty easy to review, you just need one check per file/function to make sure it really should be removed.

Rerolled and included remaining deprecations.

If large issues are being committed, I'm fine with it here too.

Just to say for deprecation removals, especially when the diffstat is like this 16 files changed, 4 insertions, 1163 deletions., per-module seems the best way. Very little chance of conflicting with other deprecation removal patches (and most other patches shouldn't touch already-deprecated code either).

If we have actual bc-layer logic that's not simply a case of removing hunks of code it might be worth splitting out sometimes.

Committed 6c69385 and pushed to 9.0.x. Thanks!

Closed #3088748: Remove the deprecated views relationship provided by content moderation to the internal ContentModerationState entity type as outdated since this patch was a superset of that one.