[FR] Add randomization to sentence validation

[HarikalarKutusu]

Is your feature request related to a problem? Please describe.
We did a workshop on Common Voice, people added several sentences. When we started to validate, everybody got the same sentences in the same order. This possibly resulted in 15 plus votes for each sentence.

This might seem a special case for this workshop, but it is also valid for campaigns.

Describe the solution you'd like

1. The feed to different people should be randomized.
2. If possible, when the sentence gets two Yes/No votes, it should not be provided to others.

Additional context
This is possibly because the data is cached by the server, maybe shuffling this before sending will solve this issue.