Add division tag around image tags

[beutlich]

See also #3549.

[HansOlsson]

Looks good to me.

[tobolar]

IMO this check is needless as long as there is no corresponding rule given. Clear, there is a discussion in #3549 but no decission so far.

[maltelenz]

I haven't reviewed the python changes.

I agree with @tobolar that it makes sense to explicitly add a guideline to our documentation if we agree this is the way to go.

That said, these specific changes (to the mo files) look good to me.

[beutlich]

Something like this?

Figures shall be placed outside of paragraphs.
Figures shall not be placed directly within the body context.

[tobolar]

@christiankral Are you able to contribute to this discussion? You are in the end the Library officer of UsersGuide.

To be clear: I like the idea of <div>environment. But not sure how this works within another environments, e.g. figures within lists.

[beutlich]

@tobolar OK for you to merge this PR anyway and update the guide lines later in a separate issue?

[tobolar]

I don't know the procedure in detail but wouldn't it lead to lot of warnings being simply ignored? The check itself is fine to me, so ok to merge.