Optimize Term table display

Summary

The terms table can take dozens of seconds to load for large corpora (40s for a 120k doc / 2000k terms). Although is it normal to have longer waiting time for large corpora, it seems that there are optimization margins because :

1. when loading a map term, the page loads, displays a maps list for few millisec then load about the same amount of time before actual displaying the final result. It is as if the query where done twice in a row. There is no such behavior with the loading of the full list.
2. When loading "All terms", the loading time is halves (there is no blinking). So it's strange that the loading of all the terms goes faster than the loading of only the Map terms
3. If you change the pagination, this fetch again the same data where it could just use the displayed data but reorganize them differently.
4. Same when you choose to display monograms (resp. multi-grams), all the data are fetched again where it should be possible to only apply filter on client side data.

At least for 1-3 it should be possible to find faster ways to implement this.

Beware that a standard worflow for mapList is query mapTerms -> display only mono (resp.) multi terms -> change the pagination. In that case, you wait three times the reload of the same data to get what you want to display. For large corpora is about 2min waiting time each time you want to display and work on mapList. So optimizing loading times is really essential.