Make Upcast and Downcast writers more consistent

[f1ames]

Extracted from ckeditor/ckeditor5-engine#1503.

When working on UpcastWriter we made it as much consistent as possible with DowncastWriter. However, DowncastWriter has some inconsistencies itself which could be fixed:

remove() is inconsistent only because downcastWriter takes a range only. TBH, I'd change downcastWriter to accept both range and element and simply check if element is passed, if so, create a range on it (Range.createOn()). When this is done, the methods are consistent enough to get a thumbs up from me.

rename() is available in DowncastWriter and has wrong order. I'd change the order there.

[f1ames]

The only thing which makes me sad about this change is that after it the DowncastWriter.rename() method signature will be inconsistent with the model/writer.rename() method signature. However, since those writers does not have so much in common as Upcast and Downcast writers I think it is acceptable.
Still it may bring some confusion for developers who use both model and view writers frequently.

[scofalik]

It makes me sad too. Could you please create a follow-up ticket for that?