Make API responses consistent

There are a few examples of inconsistent api responses.

We should do a look through and see if there are other similar inconsistencies, make a list here, and try to update them all at once. These could later be broken into separate issues if needed.

List:
- `/api/teams` 200 get response is an array of objects, while `/api/clients` 200 get response is an object with a `clients` property which is an array of objects
- user OSM id should always be named the same thing and be either a string or an integer. for instance, in the individual team response in the member array the id is a string and represents the osm id but in the moderator array both id and osm_id exist and both are integers
- catch errors in route handlers and provide specific, readable errors instead of whatever the db or other dependency is throwing, for example instead of `"insert into \"team\" (\"bio\", \"hashtag\", \"name\") values ($1, $2, $3) returning *, ST_asGeoJSON(\"location\") as \"location\" - duplicate key value violates unique constraint \"team_hashtag_unique\""` we should say something more clear like ``The hashtag `hashtagname` is already taken``. (obvs `hashtag` will be replaced by `tags` but this is just an example)