Add new api for wikipedia image info

[zexigong]

No description provided.

[zexigong]

Wikidocumentaries/wikidocumentaries-ui#92

[tuukka]

Thank you for this pull request! I wanted to investigate this more myself but I haven't had the time. Perhaps you can answer some of the questions I have:

1. What if anything does the function getWikidataImagesFromWikipedia have to do with Wikidata?
2. Is there a reason to get the information one image at a time, or would it be better to get all images with one request? Example
3. Is there a reason to return the raw imageinfo response, or would it be better to convert the response to the format that the Wikidocumentaries image viewer uses?
4. Would it make sense to share code with wikimedia-commons.js, which does similar things?

[zexigong]

1. It is a typo. Will fix that in the new commit.
2. I decided to get the information one image at a time for two reasons:

• I have tried to get all images with one request. The image metadata returned is not always ordered. There will be extra works to make the metadata ordered.
• Wikipedia get the information one image at a time.
  There is no significant latency difference between two approaches. I could try to get the information together if you think it is a better approach.

3. Yes I will convert the response to the format image viewer uses at backend. Previously I did that work at frontend.
4. It is hard to share the entire code here. The urls and required params are different. The converting logic can be shared. I will create a util function in my next commit.
   Thanks for your insight!

[zexigong]

Hi @tuukka, in the new commit

• Fixed wikidata typo
• Converted the response to the format that the Wikidocumentaries image viewer uses at the backend
• Shared the code with wikimedia-commons.js by creating a new util function to process the data
• Added more imageviewer fields in the new util function