"Use prepared questions" screen can take time to load

[chrqls]

Relative issue: SMILEConsortium#109

[chrqls]

The problem

If we have a lot of IQSets preloaded in IQManager with sometimes images in them (in my case 9 IQSets containing 7-8 questions + an IQSet of 23 questions), the screen "Use prepared questions" can take a lot of time to load (between 20-30s to display).

The reason

If we have 10 iqsets, the teacher app makes 10 requests /smile/iqset/<key> to the server to get specific values such as the number of questions or the data to preview the iqset ( because /smile/iqsets does not deliver these values)

The solution

To fix this performance issue, that might be interesting to prepare these data directly from the server, at least adding the size of each iqset in /smile/iqsets

[chrqls]