api responses should return ints where appropriate

[tybug]

eg https://api.umd.io/v1/courses/CCJS225/sections/0101 returns:

[
   {
      "course":"CCJS225",
      "section_id":"CCJS225-0101",
      "semester":"202108",
      "number":"0101",
      "seats":"6",
      "meetings":[
         {
            "days":"TuTh",
            "room":"1120",
            "building":"SQH",
            "classtype":"",
            "start_time":"9:30am",
            "end_time":"10:45am"
         },
         {
            "days":"TuTh",
            "room":"1120",
            "building":"SQH",
            "classtype":"",
            "start_time":"9:30am",
            "end_time":"10:45am"
         }
      ],
      "open_seats":"0",
      "waitlist":"07",
      "instructors":[
         "Jessica Morabito"
      ]
   }
]

all of seats, open_ seats, and waitlist should be ints instead. This would technically be a breaking change.