feat: Add charts API (#811)

* Utilizes renderChartConfig and CH client to query for chart data
* Implements API input schema
* Adds lots of tests

Testing Notes:
* To use swagger, go to localhost:8000/api/v2/docs
* Authorize using your access key found in localhost:8000/me
* Under the charts route, click "Try it out"
* Use example payload:
*
```
{
  "startTime": <insert valid timestamp ms>,
  "endTime": <insert valid timestamp ms>,
  "granularity": "1h",
  "series": [
    {
      "sourceId": "<insert valid sourceid>",
      "aggFn": "count",
      "where": "SeverityText:error",
      "groupBy": []
    }
  ]
}
```


It was easiest for me to go to the UI, create a new chart and grab the sourceid and start/end timestamps from the URL, plug it in and profit.

Note: It was apparent to me that we will need to provide at least GET support for sources, otherwise that ID is not easily obtained.

Ref: HDX-1651

Author: teeohhem

packages/api/src/controllers/sources.ts

@@ -4,6 +4,10 @@ export function getSources(team: string) {
   return Source.find({ team });
 }
 
+export function getSource(team: string, sourceId: string) {
+  return Source.findOne({ _id: sourceId, team });
+}
+
 export function createSource(team: string, source: Omit<ISource, 'id'>) {
   return Source.create({ ...source, team });
 }