Basic support for inline video

* ported https://gerrit.wikimedia.org/r/#/c/83503/ from upstream ve.dm.MWInlineImageNode can be easly extended
* tests for this change are easly implementable but depend on wikia-block-media-node to be merged first
Fix typos.
Merge pull request #1480 from Wikia/VE-inline-video

Basic support for inline video