Refactor API get videos and some fixes

I was testing Shinobi and noticed that Videos List API calls got slower when there is 1000 or so videos. Looked at API endpoint and did not like what I saw.

Changes are:

• using knex instead of generation raw sql, doing that fixed some SQL injections
• archived query parameter commented out as it's not implemented yet
• added new dependency express-validator for validating request query parameters
• on invalid query parameters error is responded with HTTP code 422 and example body when used wrong dates:

  {
    "errors":[
      {"value":"20a19-07-04T21:15:39Z","msg":"Invalid start date","param":"start","location":"query"},
      {"value":"20cd19-07-06T21:15:39aa","msg":"Invalid end date","param":"end","location":"query"}
    ]
  }

• extracted get videos api resolver into separate module
• changed process module to be able expose s global. Needed to get knex instance.

TODO:

• s.auth should also be refactored, looked scary right now :)
• libs/webServerPaths.js way too long, API endpoints should be extracted to separate files